View source for Slum

{{use mdy dates|date=October 2024}}
{{short description|Highly populated urban residential area consisting mostly of decrepit housing units}}
{{other uses}}
{{pp|small=yes}}
[[File:Sl2022.png|alt=https://ourworldindata.org/grapher/share-of-urban-population-living-in-slums?time=latest|upright=1.4|thumb|Share of urban population living in slums (2022)]]
{{Infobox
| title            = Slums in various countries
| image            = {{image array|perrow=3|width=115|height=85
| image1  = Kibera 5 2020.jpg| caption1 = [[Nairobi]], Kenya
| image3  = Jakarta slumhome 2.jpg| caption3 = [[Jakarta]], Indonesia
| image4  = Soweto township.jpg| caption4 = [[Johannesburg]], South Africa
| image5  = Morro_da_Providência.jpg| caption5 = [[Rio de Janeiro]], Brazil
| image8  = Mexico City suburbs Cuautepec.JPG| caption8 = [[Tlalnepantla de Baz]], Mexico
| image9  = China Slum December 2006.jpg| caption9 = [[Shanghai]], China
| image10 = KULUPWADI.jpg| caption10 = [[Mumbai]], India
| image11 =| caption11 = Little Mexico Colonia, Texas, United States
| image13 = Barrio Caracas.jpg| caption13 = [[Caracas]], Venezuela
| image15 = Swakopmund DRC.JPG| caption15 = [[Swakopmund]], Namibia
}}
}}
A '''slum''' is a [[Pejorative|derogatory term]] for a highly populated [[Urban area|urban]] [[residential area]] consisting of densely packed housing units of weak build quality and often associated with [[poverty]]. The [[infrastructure]] in slums is often deteriorated or incomplete, and they are primarily inhabited by impoverished people.<ref name="whyslums">[http://www.unhabitat.org/downloads/docs/4625_51419_GC%2021%20What%20are%20slums.pdf "What are slums and why do they exist?"] {{webarchive|url=https://web.archive.org/web/20110206143558/http://www.unhabitat.org/downloads/docs/4625_51419_GC%2021%20What%20are%20slums.pdf |date=2011-02-06}} UN-Habitat, Kenya (April 2007)</ref> 

Although slums are usually located in [[urban area]]s, they can be located in [[suburban area]]s where housing quality is low and living conditions are poor.<ref>{{Cite book |title=Encyclopedia of the City |last=Caves |first=R. W. |publisher=Routledge |year=2004 |isbn=978-0-415-25225-6 |page=601}}</ref> Slum residences vary from [[shanty town|shanty]] houses to professionally built dwellings which, because of poor-quality construction or lack of basic maintenance, have deteriorated.<ref name="UN-Habitat 2007 Press Release">[http://www.unhabitat.org/downloads/docs/4625_51419_GC%2021%20What%20are%20slums.pdf UN-Habitat 2007 Press Release] {{webarchive|url=https://web.archive.org/web/20110206143558/http://www.unhabitat.org/downloads/docs/4625_51419_GC%2021%20What%20are%20slums.pdf|date=2011-02-06}} on its report, "The Challenge of Slums: Global Report on Human Settlements 2003".</ref> While slums differ in size and other characteristics, most lack reliable [[sanitation]] services, [[Water supply|supply of clean water]], reliable electricity, [[law enforcement]], and other basic services. The [[United Nations]] defines slums as ".... [[Informal housing|informal settlements]] lacking one or more of the following conditions: access to improved water, access to improved sanitation, sufficient living area, housing durability, and security of tenure."<ref>{{cite web |title=Population living in slums |url=https://databank.worldbank.org/metadataglossary/world-development-indicators/series/EN.POP.SLUM.UR.ZS |access-date=May 15, 2022 |publisher=United Nations}}</ref>

Due to increasing urbanization of the general populace, slums became common in the 19th to late 20th centuries in the United States and Europe.<ref name="Lawrence Vale 2007">Lawrence Vale (2007), ''From the Puritans to the Projects: Public Housing and Public Neighbors'', Harvard University Press, {{ISBN|978-0674025752}}</ref>{{page needed|date=October 2024}}<ref name="Ashton2006">{{cite journal |pmc=2588079 |first1=J R |last1=Ashton |year=2006 |title=Back to back housing, courts, and privies: the slums of 19th century England |journal=Journal of Epidemiology & Community Health |volume=60 |issue=8 |page=654}}</ref> Slums are still predominantly found in urban regions of [[developing countries]], but are also still found in [[Economic development|developed economies]].<ref name="Slums: Past, Present and Future">[https://web.archive.org/web/20130921055319/http://www.unhabitat.org/documents/media_centre/sowcr2006/SOWCR%204.pdf "Slums: Past, Present and Future"] United Nations Habitat (2007)</ref><ref name="grhs2003">[https://web.archive.org/web/20130921055009/http://www.unhabitat.org/downloads/docs/grhs.2003.key.pdf "The challenge of slums – Global report on Human Settlements"], United Nations Habitat (2003)</ref> The world's largest slum city is found in [[Orangi]] in [[Karachi]], Pakistan.<ref>Mike Davis, ''Planet of Slums'' [« Le pire des mondes possibles : de l'explosion urbaine au bidonville global »], La Découverte, Paris, 2006 ({{ISBN|978-2-7071-4915-2}})</ref>{{page needed|date=October 2024}}<ref>Daniel Tovrov (December 9, 2011). [http://www.ibtimes.com/5-biggest-slums-world-381338 "5 Biggest Slums in the World"]. {{Webarchive|url=https://web.archive.org/web/20130921084023/http://www.ibtimes.com/5-biggest-slums-world-381338 |date=2013-09-21}}, ''International Business Times''.</ref><ref>Craig Glenday, editor. ''Guinness World Records''. 2013. Bantam. {{ISBN|978-0-345-54711-8}}. Page 277.</ref>

Slums form and grow in different parts of the world for many different reasons. Causes include rapid [[Rural flight|rural-to-urban migration]], [[economic stagnation]] and [[Economic depression|depression]], high [[unemployment]], poverty, [[informal economy]], forced or manipulated ghettoization, poor planning, politics, [[natural disaster]]s, and [[Social conflict|social conflicts]].<ref name="whyslums" /><ref>Patton, C. (1988). ''Spontaneous shelter: International perspectives and prospects''. Philadelphia: Temple University Press.</ref>{{page needed|date=October 2024}}<ref name="grhs2011" /> Strategies tried to reduce and transform slums in different countries, with varying degrees of success, include a combination of slum removal, slum relocation, slum upgrading, [[urban planning]] with citywide infrastructure development, and [[public housing]].<ref name="unh2007a" /><ref>Mona Serageldin, Elda Solloso, and Luis Valenzuela (March 2006). [http://www.globalurban.org/GUDMag06Vol2Iss1/Serageldin,%20Solloso,%20&%20Valenzuela.htm "Local Government Actions to Reduce Poverty and Achieve The Millennium Development Goals"] {{Webarchive|url=https://web.archive.org/web/20191022014457/http://www.globalurban.org/GUDMag06Vol2Iss1/Serageldin%2C%20Solloso%2C%20%26%20Valenzuela.htm |date=2019-10-22}}. ''Global Urban Development Magazine'', Vol 2, Issue 1.</ref>
==Etymology and nomenclature==
[[File:London slums Wellcome L0000877.jpg|thumb|right|19th century slum, London]]
It is thought<ref>Douglas Harper (2001). [http://www.etymonline.com/index.php?term=slum "Slum"] {{Webarchive|url=https://web.archive.org/web/20140203031630/http://www.etymonline.com/index.php?term=slum |date=2014-02-03}} ''Etymology Dictionary''.</ref> that ''slum'' is a British slang word from the [[East End]] of London meaning "room", which evolved to "back slum" around 1845 meaning 'back alley, street of poor people.'

Numerous other non-English terms are often used interchangeably with ''slum'': [[shanty town]], [[favela]], [[Rookery (slum)|rookery]], [[gecekondu]], [[skid row]], [[barrio]], [[ghetto]], [[banlieue]], bidonville, taudis, bandas de miseria, barrio marginal, morro, paragkoupoli, loteamento, barraca, musseque, [[:tl:iskuwater|iskuwater]], [[inner city]], tugurio, solares, mudun safi, kawasan kumuh, karyan, medina achouaia, brarek, ishash, galoos, tanake, baladi, [[:ru:Трущобы|trushchoby]], chalis, katras, zopadpattis, ftohogeitonia, basti, estero, looban, dagatan, umjondolo, watta, udukku, and chereka bete.<ref>''Slums of the World: The Face of Urban Poverty in the New Millennium?'' {{ISBN|92-1-131683-9}}, UN-Habitat; page 30.</ref>

The word ''slum'' has negative connotations, and using this label for an area can be seen as an attempt to delegitimize that land use when hoping to repurpose it.<ref>{{cite journal |doi=10.1177/095624788900100201 |title=Beyond the stereotype of 'slums' |journal=Environment and Urbanization |volume=1 |issue=2 |pages=2–5 |year=2016 |s2cid=220803082 |doi-access=free}}</ref>

==History==
[[File:Jacob Riis - Bandits' Roost.jpg|thumb|One of the many New York City slum photographs of [[Jacob Riis]] ({{circa}} 1890). Filth can be seen on the street, with drying laundry hanging between buildings.]]
[[File:Jacob Riis, Lodgers in a Crowded Bayard Street Tenement.jpg|thumb|Inside of a slum house, from Jacob Riis photo collection of New York City (ca 1890).]]
[[File:Poverty map old nichol 1889.jpg|thumb|Part of [[Charles Booth (philanthropist)|Charles Booth]]'s [[poverty map]] showing the [[Old Nichol]], a slum in the [[East End of London]]. Published 1889 in [[Life and Labour of the People in London]]. The red areas are "middle class, well-to-do", light blue areas are "poor, 18s to 21s a week for a moderate family", dark blue areas are "very poor, casual, chronic want", and black areas are the "lowest class...occasional labourers, street sellers, loafers, criminals and semi-criminals".]]

Before the 19th century, rich and poor people lived in the same districts, with the wealthy living on the high streets, and the poor in the service streets behind them. But in the 19th century, wealthy and upper-middle-class people began to move out of the central part of rapidly growing cities, leaving poorer residents behind.<ref>Flanders, Judith (May 15, 2014) [https://www.bl.uk/romantics-and-victorians/articles/slums "Discovering Literature: Romantics & Victorians: Slums"] [[British Library]]</ref>

Slums were common in the United States and Europe before the early 20th century. London's East End is generally considered the locale where the term originated in the 19th century, where massive and rapid urbanization of the dockside and industrial areas led to intensive overcrowding in a warren of post-medieval streetscape. The suffering of the poor was described in popular fiction by moralist authors such as [[Charles Dickens]] – most famously ''[[Oliver Twist]]'' (1837–1839) and echoed the [[Christian socialism|Christian Socialist]] values of the time, which soon found legal expression in the [[Public Health Act 1848]]. As the [[slum clearance]] movement gathered pace, deprived areas such as [[Old Nichol]] were fictionalised to raise awareness in the middle classes in the form of moralist novels such as ''[[A Child of the Jago]]'' (1896) resulting in [[Urban renewal#England|slum clearance]] and reconstruction programmes such as the [[Boundary Estate]] (1893-1900) and the creation of charitable trusts such as the [[Peabody Trust]] founded in 1862 and [[Joseph Rowntree Foundation]] (1904) which still operate to provide [[Decent Homes Standard|decent housing]] today.

Slums are often associated with the [[British Isles]] during the [[Victorian era]], particularly in industrial towns. [[Friedrich Engels]] described these neighborhoods as "cattle-sheds for human beings".<ref>Mike Pitts (August 27, 2009). [https://www.theguardian.com/science/2009/aug/28/archaeology-manchester-victorian-slums "Unearthing Manchester's Victorian slums"] {{Webarchive|url=https://web.archive.org/web/20160920081317/https://www.theguardian.com/science/2009/aug/28/archaeology-manchester-victorian-slums |date=2016-09-20}} ''The Guardian''.</ref> These were generally still inhabited until the 1940s, when the British government started [[urban renewal|slum clearance]] and built new [[council house]]s.<ref>[http://fet.uwe.ac.uk/conweb/house_ages/council_housing/section4.htm "The History of Council Housing"] {{Webarchive|url=https://web.archive.org/web/20130921053314/http://fet.uwe.ac.uk/conweb/house_ages/council_housing/section4.htm |date=2013-09-21}} University of the West of England, Bristol (2008)</ref> There are still examples left of slum housing in the UK, but many have been removed by government initiative, redesigned and replaced with better public housing. In Europe, slums were common.<ref>Eckstein, Susan. 1990. "Urbanization Revisited: Inner-City Slum of Hope and Squatter Settlement of Despair". ''World Development 18'': 165–181</ref><ref>Roger W. Caves, editor (2005). ''Encyclopedia of the City''. {{ISBN|978-0415252256}}. page 410; also see "Slum", ''Encyclopædia Britannica'' (2001).</ref> By the 1920s it had become a common slang expression in England, meaning either various [[Tavern|taverns]] and eating houses, "loose talk" or gypsy language, or a room with "low going-ons". In ''[[Life in London (novel)|Life in London]]'' (1821) [[Pierce Egan]] used the word in the context of the "back slums" of Holy Lane or [[St Giles, London|St Giles]]. A footnote defined slum to mean "low, unfrequent parts of the town". [[Charles Dickens]] used the word slum in a similar way in 1840, writing "I mean to take a great, London, back-slum kind walk tonight". Slum began to be used to describe bad housing soon after and was used as alternative expression for [[Rookery (slum)|rookeries]].<ref name="Dyos 1982">{{Cite book |last=Dyos |first=H.J. |author2=Cannadine, David |author3=Reeder, David |title=Exploring the urban past: Essays in urban history |publisher=Cambridge University Press |year=1982 |url=https://books.google.com/books?id=au06FldIsn4C&q=%22cardinal+wiseman%22+slum |isbn=978-0-521-28848-4}}</ref>{{page needed|date=October 2024}} In 1850 the Catholic [[Cardinal Wiseman]] described the area known as [[Devil's Acre]] in [[Westminster]], London as follows:

<blockquote>Close under the Abbey of Westminster there lie concealed labyrinths of lanes and potty and alleys and slums, nests of ignorance, vice, depravity, and crime, as well as of squalor, wretchedness, and disease; whose atmosphere is typhus, whose ventilation is cholera; in which swarms of huge and almost countless population, nominally at least, Catholic; haunts of filth, which no sewage committee can reach – dark corners, which no lighting board can brighten.<ref>{{Cite book |last=Ward |first=Wilfrid Philip |title=The Life and Times of Cardinal Wiseman, Volume 1 |year=2008 |publisher=BiblioBazaar |page=568 |url=https://books.google.com/books?id=M4mhP5Dc9NMC&q=%22cardinal+wiseman%22+slum |isbn=978-0-559-68852-2}}</ref></blockquote>

This passage was widely quoted in the national press, leading to the popularization of the word ''slum'' to describe bad housing.<ref>{{Cite book |last=Dyos |first=H.J. |author2=Cannadine, David |author3=Reeder, David |title=Exploring the urban past: essays in urban history |publisher=Cambridge University Press |year=1982 |page=240 |url=https://books.google.com/books?id=au06FldIsn4C&q=%22cardinal+wiseman%22+slum#v=snippet&q=%22cardinal%20wiseman%22%20slum&f=false |isbn=978-0-521-28848-4}}</ref><ref>{{Cite book |last=Wohl |first=Anthony S. |title=The eternal slum: housing and social policy in Victorian London |publisher=Transaction Publishers |year=2002 |page=5 |url=https://books.google.com/books?id=1IgeAuQNm_UC&q=%22cardinal+wiseman%22+slum |isbn=978-0-7658-0870-7}}</ref>

[[File:Rear of 114 -120 Elizabeth Street.jpg|thumb|A slum dwelling in [[Toronto, Ontario]], Canada, about 1936.<ref>[http://www.toronto.ca/culture/history/history-1901-50.htm "Toronto Culture – Exploring Toronto's past – The First Half of the 20th Century, 1901–51"]. City of Toronto, Ontario, Canada (2011)</ref><ref>{{cite web |url=http://www.historytothepeople.ca/remembering-st-johns-ward-the-images-of-toronto-city-photographer-arthur-s-goss/ |title=Remembering St. John's Ward: The Images of Toronto City Photographer, Arthur S. Goss |access-date=July 23, 2015 |archive-url=https://web.archive.org/web/20150723175443/http://www.historytothepeople.ca/remembering-st-johns-ward-the-images-of-toronto-city-photographer-arthur-s-goss/ |archive-date=July 23, 2015 |url-status=live}}</ref>]]

In France as in most industrialised European capitals, slums were widespread in Paris and other urban areas in the 19th century, many of which continued through first half of the 20th century. The first [[cholera epidemic of 1832]] triggered a political debate, and [[Louis-René Villermé|Louis René Villermé]] study<ref>Nancy Krieger (2001). "Historical roots of social epidemiology". ''International Journal of Epidemiology''. 30 (4): 899–900</ref> of various [[arrondissement]]s of Paris demonstrated the differences and connection between slums, poverty and poor health.<ref>Ann-Louise Shapiro (1985), ''Housing the Poor of Paris'', 1850–1902, {{ISBN|978-0299098803}}</ref>{{page needed|date=October 2024}} [[Melun Act of 1851|Melun Law]] first passed in 1849 and revised in 1851, followed by establishment of Paris Commission on Unhealthful Dwellings in 1852 began the social process of identifying the worst housing inside slums, but did not remove or replace slums. 

After [[World War II]], French people started mass migration from rural to urban areas of France. This demographic and economic trend rapidly raised rents of existing housing as well as expanded slums. French government passed laws to block increase in the rent of housing, which inadvertently made many housing projects unprofitable and increased slums. In 1950, France launched its [[HLM|Habitation à Loyer Modéré]]<ref name="URO habitat">[http://www.convergence-lr.fr/evenement/1/hlm-ideesrecues-2012.pdf "10 idées reçues sur les HLM"] {{webarchive|url=https://web.archive.org/web/20131126045403/http://www.convergence-lr.fr/evenement/1/hlm-ideesrecues-2012.pdf |date=2013-11-26}}, Union sociale pour l'habitat, February 2012</ref><ref>[http://www.housingeurope.eu/publication/social-housing-country-profiles/social-housing-in/fr France – public housing] {{Webarchive|url=https://web.archive.org/web/20130518193504/http://www.housingeurope.eu/publication/social-housing-country-profiles/social-housing-in/fr |date=2013-05-18}} European Union</ref> initiative to finance and build public housing and remove slums, managed by techniciens – urban technocrats.,<ref>[http://juh.sagepub.com/content/38/6/1021.short "Ordering the Disorderly Slum – Standardizing Quality of Life in Marseille Tenements and Bidonvilles"] {{Webarchive|url=https://web.archive.org/web/20161014164930/http://juh.sagepub.com/content/38/6/1021.short |date=2016-10-14}} Minayo Nasiali, ''Journal of Urban History'' November 2012 vol. 38 no. 6, 1021–1035</ref> and financed by Livret A<ref>[http://www.connexionfrance.com/Livret-savers-interest-rate-Banque-ceiling-tax-14884-view-article.html "Livret A rate falls to 1.25%"] {{Webarchive|url=https://web.archive.org/web/20130822001538/http://www.connexionfrance.com/Livret-savers-interest-rate-Banque-ceiling-tax-14884-view-article.html |date=2013-08-22}} ''The Connexion'' (July 18, 2013)</ref> – a tax free savings account for French public. Some slums remain in the early 21st century in France, most of which are dismantled after a few months, the largest being the "Petite Ceinture" slum on the northern Paris decommissioned train tracks.<ref>{{Cite web|url=https://www.bfmtv.com/societe/logement/paris-le-bidonville-de-la-petite-ceinture-evacue_AN-201711280018.html|title=Paris: le bidonville de la Petite ceinture évacué|website=BFMTV}}</ref>

New York City is believed to have created the United States' first slum, named the [[Five Points, Manhattan#The Slum|Five Points]] in 1825, as it evolved into a large urban settlement.<ref name="Ashton2006" /><ref name="nyt2001">Kevin Baker (September 30, 2001). [https://www.nytimes.com/2001/09/30/books/the-first-slum-in-america.html "The First Slum in America"] {{Webarchive|url=https://web.archive.org/web/20161206145031/http://www.nytimes.com/2001/09/30/books/the-first-slum-in-america.html |date=2016-12-06}}. ''The New York Times''.</ref> Five Points was named for a lake named [[Five Points, Manhattan#Collect Pond|Collect]].<ref name="nyt2001" /><ref>Solis, Julia. ''New York Underground: The Anatomy of a City''. p. 76</ref> which, by the late 1700s, was surrounded by slaughterhouses and tanneries which emptied their waste directly into its waters. Trash piled up as well and by the early 1800s the lake was filled up and dry. On this foundation was built Five Points, the United States' first slum. Five Points was occupied by successive waves of freed slaves, Irish, then Italian, then Chinese, immigrants. It housed the poor, rural people leaving farms for opportunity, and the persecuted people from Europe pouring into New York City. Bars, bordellos, squalid and lightless tenements lined its streets. Violence and crime were commonplace. Politicians and social elite discussed it with derision. Slums like Five Points triggered discussions of [[affordable housing]] and slum removal. As of the start of the 21st century, Five Points slum had been transformed into the [[Little Italy, Manhattan|Little Italy]] and Chinatown neighborhoods of New York City, through that city's campaign of massive [[urban renewal]].<ref name="Lawrence Vale 2007" />{{page needed|date=October 2024}}<ref name="nyt2001" />

Five Points was not the only slum in America.<ref>[[Gerald D. Suttles|Suttles, Gerald D.]] 1968. ''The Social Order of the Slum''. Chicago: University of Chicago Press</ref>{{page needed|date=October 2024}}<ref>Gans, Herbert J. 1962. ''The Urban Villagers''. New York: The Free Press.</ref>{{page needed|date=October 2024}} [[Jacob Riis]], [[Walker Evans]], [[Lewis Hine]] and others photographed many before World War II. Slums were found in every major urban region of the United States throughout most of the 20th century, long after the Great Depression. Most of these slums had been ignored by the cities and states which encompassed them until the 1960s' [[War on Poverty]] was undertaken by the Federal government of the United States.

A type of slum housing, sometimes called [[Poorhouse|poorhouses]], crowded [[Boston Common]], later at the fringes of the city.<ref>[http://affordablehousinginstitute.org/blogs/us/2008/10/history-of-us-public-housing-part-3-the-slum-clearance-era.html "History of US Public Housing"] {{Webarchive|url=https://web.archive.org/web/20140223121021/http://affordablehousinginstitute.org/blogs/us/2008/10/history-of-us-public-housing-part-3-the-slum-clearance-era.html |date=2014-02-23}} Affordable Housing Institute, United States (2008); See Part 1, 2 and 3</ref>

[[File:Les enfants de la zone (Ivry, 1913).jpeg|thumb|A 1913 slum dwelling midst squalor in [[Ivry-sur-Seine]], a French commune about 5 kilometers from center of [[Paris]]. Slums were scattered around Paris through the 1950s.<ref>Rosemary Wakeman, ''The Heroic City: Paris, 1945–1958'', University of Chicago Press, {{ISBN|978-0226870236}}. pages 45–61.</ref><ref>Courgey (1908), "Recherche et classement des anormaux: enquête sur les enfants des Écoles de la ville d'Ivry-sur-Seine", ''International Magazine of School Hygiene'', Ed: Sir Lauder Brunton, 395–418</ref> After ''Loi Vivien'' was passed in July 1970, France demolished some of its last major bidonvilles (slums) and resettled resident Algerian, Portuguese and other migrant workers by the mid-1970s.<ref>[http://www.metropolitiques.eu/Cites-de-transit-the-urban.html "Cités de transit": the urban treatment of poverty during decolonisation] {{Webarchive|url=https://web.archive.org/web/20131004215314/http://www.metropolitiques.eu/Cites-de-transit-the-urban.html |date=2013-10-04}} Muriel Cohen & Cédric David, Metro Politiques (March 28, 2012)</ref><ref>[http://fresques.ina.fr/reperes-mediterraneens/fiche-media/Repmed00407/le-dernier-bidonville-de-nice.html "Le dernier bidonville de Nice"] {{Webarchive|url=https://web.archive.org/web/20131004213739/http://fresques.ina.fr/reperes-mediterraneens/fiche-media/Repmed00407/le-dernier-bidonville-de-nice.html |date=2013-10-04}} Pierre Espagne, Reperes Mediterraneens (1976)</ref>]]

[[Rio de Janeiro]] documented its first slum in 1920 census. By the 1960s, over 33% of population of Rio lived in slums, 45% of [[Mexico City]] and [[Ankara]], 65% of [[Algiers]], 35% of [[Caracas]], 25% of [[Lima]] and [[Santiago]], 15% of [[Singapore]]. By 1980, in various cities and towns of Latin America alone, there were about 25,000 slums.<ref>Janice Perlman (1980). ''The Myth of Marginality: Urban Poverty and Politics in Rio de Janeiro''. University of California Press. {{ISBN|978-0520039520}}. pages 12–16.</ref>

==Causes that create and expand slums==
Slums sprout and continue for a combination of demographic, social, economic, and political reasons. Common causes include rapid rural-to-urban migration, poor planning, economic stagnation and depression, poverty, high unemployment, informal economy, colonialism and segregation, politics, natural disasters and social conflicts.

===Rural–urban migration===
[[File:kibera.jpg|thumb|[[Kibera]] slum in [[Nairobi]], Kenya, the second-largest slum in Africa<ref name="imcworldwide">{{cite web |url=http://www.imcworldwide.org/content/article/detail/766/ |title=International Medical Corps – International Medical Corps |access-date=July 23, 2015 |archive-url=https://web.archive.org/web/20110728132453/http://www.imcworldwide.org/content/article/detail/766/ |archive-date=July 28, 2011}}</ref><ref>{{Cite web |url=http://www.unhabitat.org/content.asp?typeid=19&catid=548&cid=4962 |title=Participating countries |access-date=2009-01-21 |archive-url=https://web.archive.org/web/20090114031916/http://www.unhabitat.org/content.asp?typeid=19&catid=548&cid=4962 |archive-date=2009-01-14 |url-status=live}}</ref><ref>[http://www.dominionpaper.ca/articles/1703 "Machetes, Ethnic Conflict and Reductionism"] {{Webarchive|url=https://web.archive.org/web/20080519150442/http://www.dominionpaper.ca/articles/1703 |date=2008-05-19}} ''[[The Dominion (Canada)|The Dominion]]''</ref> and third-largest in the world.<ref name="imcworldwide" />]]

Rural–urban migration is one of the causes attributed to the formation and expansion of slums.<ref name="whyslums" /> Since 1950, world population has increased at a far greater rate than the total amount of arable land, even as [[agriculture]] contributes a much smaller percentage of the total economy. For example, in India, agriculture accounted for 52% of its GDP in 1954 and only 19% in 2004;<ref>{{Cite web |url=http://planningcommission.nic.in/data/datatable/2504/databook_%2029.pdf |title=Gross Domestic Product (GDP) from Agriculture and Allied Sector and its Percentage Share to Total GDP (1954-55 to 2012-13) |access-date=2013-09-16 |archive-url=https://web.archive.org/web/20131024061050/http://planningcommission.nic.in/data/datatable/2504/databook_%2029.pdf |archive-date=2013-10-24 }}</ref> in Brazil, the 2050 GDP contribution of agriculture is one-fifth of its contribution in 1951.<ref>[http://www.brookings.edu/~/media/research/files/papers/2008/5/brazil%20agriculture%20barros/05_brazil_agriculture_barros.pdf Brazil: The Challenges in Becoming an Agricultural Superpower] {{Webarchive|url=https://web.archive.org/web/20131023053833/http://www.brookings.edu/~/media/research/files/papers/2008/5/brazil%20agriculture%20barros/05_brazil_agriculture_barros.pdf |date=2013-10-23}} Geraldo Barros, Brookings Institution (2008)</ref> Agriculture, meanwhile, has also become higher yielding, less disease prone, less physically harsh and more efficient with tractors and other equipment. The proportion of people working in agriculture has declined by 30% over the last 50 years, while global population has increased by 250%.<ref name="whyslums" />

Many people move to [[urban areas]] primarily because cities promise more jobs, better schools for poor's children, and diverse income opportunities than subsistence farming in [[rural areas]].<ref>Judy Baker (2008). [https://archive.today/20130916233437/http://go.worldbank.org/KT759KE9S0 "Urban Poverty – An Overview"]. The World Bank.</ref> For example, in 1995, 95.8% of migrants to [[Surabaya]], Indonesia reported that jobs were their primary motivation for moving to the city.<ref>Tjiptoherijanto, Prinjono, and Eddy Hasmi. "Urbanization and Urban Growth in Indonesia". ''Asian Urbanization in the New Millennium''. Ed. Gayl D. Ness and Prem P. Talwar. Singapore: Marshall Cavendish Academic, 2005., page 162</ref> However, some rural migrants may not find jobs immediately because of their lack of skills and the increasingly competitive job markets, which leads to their financial shortage.<ref name="Todaro">{{cite journal |last=Todaro |first=Michael P. |title=A Model of Labour Migration and Urban Unemployment in Less Developed Countries |journal=The American Economic Review |year=1969 |volume=59 |issue=1 |pages=138–148}}</ref> Many cities, on the other hand, do not provide enough low-cost [[housing]] for a large number of rural-urban migrant workers. Some rural–urban [[migrant workers]] cannot afford housing in cities and eventually settle down in only affordable slums.<ref name="Craster">{{cite journal |last=Craster |first=Charles V |title=Slum Clearance: The Newark Plan |journal=American Journal of Public Health and the Nation's Health |year=1944 |volume=34 |issue=9 |pages=935–940 |doi=10.2105/ajph.34.9.935 |pmid=18016046 |pmc=1625197}}</ref> Further, rural migrants, mainly lured by higher incomes, continue to flood into cities. They thus expand the existing urban slums.<ref name="Todaro" />

According to Ali and Toran, [[social networks]] might also explain rural–urban migration and people's ultimate settlement in slums. In addition to migration for jobs, a portion of people migrate to cities because of their connection with relatives or families. Once their family support in urban areas is in slums, those rural migrants intend to live with them in slums<ref>{{cite journal |last=Ali |first=Mohammed Akhter |author2=Kavita Toran |title=Migration, Slums and Urban Squalor – A case study of Gandhinagar Slum |journal=Proceedings of the Third International Conference on Environment and Health |year=2004 |pages=1–10}}</ref>

===Urbanization===
[[File:Rocinha Favela Brazil Slums.jpg|thumb|A slum in [[Rio de Janeiro]], Brazil. Rocinha favela is next to skyscrapers and wealthier parts of the city, a location that provides jobs and easy commute to those who live in the slums.]]
The formation of slums is closely linked to [[urbanization]].<ref name="Davis">{{cite book |last=Davis |first=Mike |title=Planet of Slums |year=2006 |publisher=Verso}}</ref>{{page needed|date=October 2024}} In 2008, more than 50% of the world's population lived in urban areas. In China, for example, it is estimated that the population living in urban areas will increase by 10% within a decade according to its current rates of urbanization.<ref>{{cite book |title=State of the world population 2007: unleashing the potential of urban growth |year=2007 |publisher=United Nations Population Fund |location=New York}}</ref>{{page needed|date=October 2024}} The UN-Habitat reports that 43% of urban population in [[developing countries]] and 78% of those in the least developed countries are slum dwellers.<ref name="grhs2003" />

Some scholars suggest that urbanization creates slums because local governments are unable to manage urbanization, and [[migrant workers]] without an affordable place to live in, dwell in slums.<ref name="Hammel 1964 346–358">{{cite journal |last=Hammel |first=Eugene A. |title=Some characteristics of rural village and urban slum populations on the coast of Peru |journal=Southwestern Journal of Anthropology |volume=20 |issue=4 |year=1964 |pages=346–358 |doi=10.1086/soutjanth.20.4.3629175 |s2cid=130682432}}</ref> Rapid urbanization drives economic growth and causes people to seek working and investment opportunities in urban areas.<ref name="Burke">{{cite journal |last=Patel |first=Ronak B. |author2=Thomas F. Burke |title=Urbanization—an emerging humanitarian disaster|journal=New England Journal of Medicine |year=2009 |volume=361 |issue=8 |pages=741–743 |doi=10.1056/nejmp0810878 |pmid=19692687 |s2cid=19545185 |doi-access=free}}</ref><ref name="Bolay">{{cite journal |last=Bolay |first=Jean-Claude |title=Slums and urban development: questions on society and globalisation |journal=The European Journal of Development Research |year=2006 |volume=18 |issue=2 |pages=284–298 |doi=10.1080/09578810600709492 |citeseerx=10.1.1.464.2718 |s2cid=24793439}}</ref> However, as evidenced by poor urban [[infrastructure]] and insufficient [[housing]], the local [[governments]] sometimes are unable to manage this transition.<ref>{{cite journal |last=Firdaus |first=Ghuncha |title=Urbanization, emerging slums and increasing health problems: a challenge before the nation: an empirical study with reference to state of uttar pradesh in India |journal=Journal of Environmental Research and Management |year=2012 |volume=3 |issue=9 |pages=146–152}}</ref><ref name="Clonts">{{cite journal |last=Clonts |first=Howard A. |title=Influence of urbanization on land values at the urban periphery |journal=Land Economics |year=1970 |volume=46 |issue=4 |pages=489–497 |doi=10.2307/3145522 |jstor=3145522 |bibcode=1970LandE..46..489C }}</ref> This incapacity can be attributed to insufficient funds and inexperience to handle and organize problems brought by migration and urbanization.<ref name="Bolay" /> In some cases, local governments ignore the flux of immigrants during the process of urbanization.<ref name="Burke" /> Such examples can be found in many [[List of sovereign states and dependent territories in Africa|African]] countries. In the early 1950s, many African governments believed that slums would finally disappear with economic growth in urban areas. They neglected rapidly spreading slums due to increased rural-urban migration caused by urbanization.<ref>{{cite book |title=UN-Habitat (2003b) The Challenge of Slums: Global Report on Human Settlements |year=2003 |publisher=UN-Habitat |location=Earthscan, London}}</ref>{{page needed|date=October 2024}} Some governments, moreover, mapped the land where slums occupied as undeveloped land.<ref>{{cite journal |last=Wekwete |first=K. H |title=Urban management: The recent experience, in Rakodi, C. |journal=The Urban Challenge in Africa |year=2001}}</ref>

Another type of urbanization does not involve economic growth but [[economic stagnation]] or low growth, mainly contributing to slum growth in [[Sub-Saharan Africa]] and parts of [[Asia]]. This type of urbanization involves a high rate of [[unemployment]], insufficient financial resources and inconsistent [[urban planning]] policy.<ref>{{cite book |last=Cheru |first=F |title=Globalization and uneven development in Africa: The limits to effective urban governance in the provision of basic services |year=2005 |publisher=UCLA Globalization Research Center-Africa}}</ref>{{page needed|date=October 2024}} In these areas, an increase of 1% in urban population will result in an increase of 1.84% in slum prevalence.<ref name="barimslum" />

Urbanization might also force some people to live in slums when it influences [[land use]] by transforming agricultural land into urban areas and increases land value. During the process of urbanization, some agricultural land is used for additional urban activities. More investment will come into these areas, which increases the land value.<ref>{{cite journal |last=Rancich |first=Michael T. |title=Land value changes in an area undergoing urbanization |journal=Land Economics |year=1970 |volume=46 |issue=1 |pages=32–40 |doi=10.2307/3145421 |jstor=3145421 |bibcode=1970LandE..46...32R }}</ref> Before some land is completely urbanized, there is a period when the land can be used for neither urban activities nor agriculture. The income from the land will decline, which decreases the people's incomes in that area. The gap between people's low income and the high land price forces some people to look for and construct cheap [[informal settlements]], which are known as slums in urban areas.<ref name="Clonts" /> The transformation of agricultural land also provides [[surplus labour]], as peasants have to seek jobs in urban areas as rural-urban [[migrant workers]].<ref name="Hammel 1964 346–358" />

Many slums are part of [[economies of agglomeration]] in which there is an emergence of [[economies of scale]] at the firm level, transport costs and the mobility of the industrial labour force.<ref name="Alonso" /> The increase in returns of scale will mean that the production of each good will take place in a single location.<ref name="Alonso">{{cite journal |last1=Alonso-Villar |first1=Olga |title=Large Metropolises in the Third World: An Explanation. |journal=Urban Studies |date=2001 |volume=38 |issue=8 |page=1368 |doi=10.1080/00420980120061070 |bibcode=2001UrbSt..38.1359A |s2cid=153400618}}</ref> And even though an agglomerated economy benefits these cities by bringing in specialization and multiple competing suppliers, the conditions of slums continue to lag behind in terms of quality and adequate housing. Alonso-Villar argues that the existence of transport costs implies that the best locations for a firm will be those with easy access to markets, and the best locations for workers, those with easy access to goods. The concentration is the result of a self-reinforcing process of agglomeration.<ref name="Alonso" /> Concentration is a common trend of the distribution of population. Urban growth is dramatically intense in the less developed countries, where a large number of huge cities have started to appear; which means high poverty rates, crime, pollution and congestion.<ref name="Alonso" />

=== Poor house planning ===
[[File:Slums and Skyscrapers in La Paz.jpg|thumb|right|A large slum pictured behind skyscrapers in a more developed area in [[La Paz]], Bolivia.]]
Lack of affordable low-cost housing and poor planning encourages the supply side of slums.<ref name="lse">[http://lsecities.net/media/objects/articles/istanbuls-gecekondus Istanbul's Gecekondus] {{Webarchive|url=https://web.archive.org/web/20131022184541/http://lsecities.net/media/objects/articles/istanbuls-gecekondus |date=2013-10-22}} Orhan Esen, London School of Economics and Political Science (2009)</ref> The [[Millennium Development Goals]] proposes that member nations should make a "significant improvement in the lives of at least 100 million slum dwellers" by 2020.<ref>{{cite journal |last=United Nations |title=United Nations Millennium Declaration |journal=United Nations Millennium Summit |year=2000 |url=https://www.un.org/millennium/declaration/ares552e.pdf |access-date=2017-06-29 |archive-url=https://web.archive.org/web/20180307225929/http://www.un.org/millennium/declaration/ares552e.pdf |archive-date=2018-03-07 |url-status=live}}</ref> If member nations succeed in achieving this goal, 90% of the world total slum dwellers may remain in the poorly housed settlements by 2020.<ref name="Choguill">{{cite journal |last=Choguill |first=Charles L. |title=The search for policies to support sustainable housing |journal=Habitat International |year=2007 |volume=31 |issue=1 |pages=143–149 |doi=10.1016/j.habitatint.2006.12.001}}</ref> Choguill claims that the large number of slum dwellers indicates a deficiency of practical housing policy.<ref name="Choguill" /> Whenever there is a significant gap in growing demand for housing and insufficient supply of affordable housing, this gap is typically met in part by slums.<ref name="lse" /> ''The Economist'' has observed that "good housing is obviously better than a slum, but a slum is better than none".<ref>[https://www.economist.com/britain/2012/07/14/scourge-of-slums Scourge of slums]  ''The Economist'' (July 14, 2012)</ref>

Insufficient [[financial]] resources <ref name="Walther">{{cite journal |last=Walther |first=James V. |title=Cause or Effect of Slums? |journal=Challenge |year=1965 |volume=13 |issue=14 |pages=24–25 |doi=10.1080/05775132.1965.11469790}}</ref> and lack of coordination in government bureaucracy <ref name="barimslum" /> are two main causes of poor house planning. Financial deficiency in some governments may explain the lack of affordable [[public housing]] for the poor since any improvement of the tenant in slums and expansion of [[public housing]] programs involve a great increase in the government expenditure.<ref name="Walther" /> The problem can also lie on the failure in coordination among different departments in charge of economic development, [[urban planning]], and land allocation. In some cities, governments assume that the housing [[Market (economics)|market]] will adjust the supply of housing with a change in demand. However, with little economic incentive, the housing market is more likely to develop middle-income housing rather than low-cost housing. The urban poor gradually become marginalized in the housing market where few houses are built to sell to them.<ref name="barimslum" /><ref>{{cite journal |last=Ooi |first=Giok Ling |author2=Kai Hong Phua |title=Urbanization and slum formation |journal=Journal of Urban Health |volume=84 |issue=1 |pages=27–34 |pmid=17387618 |year=2007 |doi=10.1007/s11524-007-9167-5 |pmc=1891640}}</ref>

===Colonialism and segregation===
[[File:Pottery unit in Dharavi, Mumbai.jpg|thumb|An integrated slum dwelling and informal economy inside Dharavi of [[Mumbai]]. Dharavi slum started in 1887 with industrial and segregationist policies of the British colonial era. The slum housing, tanneries, pottery and other economy established inside and around Dharavi during the British rule of India.<ref name="jn2010" /><ref>Sharma, K. (2000). ''Rediscovering Dharavi: stories from Asia's largest slum''. Penguin, {{ISBN|978-0141000237}}, pages 3–11</ref><ref>Pacione, Michael (2006), Mumbai, Cities, 23(3), pages 229–238</ref>]]

Some of the slums in today's world are a product of [[urbanization]] brought by [[colonialism]]. For instance, the [[Europeans]] arrived in [[Kenya]] in the nineteenth century and created urban centers such as [[Nairobi]] mainly to serve their financial interests. They regarded the Africans as temporary migrants and needed them only for supply of [[Employment|labour]]. The housing policy aiming to accommodate these workers was not well enforced and the government built settlements in the form of single-occupancy bedspaces. Due to the cost of time and money in their movement back and forth between rural and urban areas, their families gradually migrated to the urban centre. As they could not afford to buy houses, slums were thus formed.<ref>{{cite journal |last=Obudho |first=R. A. |author2=G. O. Aduwo |title=Slum and squatter settlements in urban centres of Kenya: Towards a planning strategy |journal=Journal of Housing and the Built Environment |year=1989 |volume=4 |issue=1 |pages=17–30 |doi=10.1007/bf02498028 |s2cid=154852140}}</ref>
[[File:KWC - 1975.jpg|thumb|[[Kowloon Walled City]], an [[Enclave and exclave|exclave]] of the [[People's Republic of China]] located in [[British Hong Kong|Hong Kong]], was the densest place on Earth in the 1980s and early 1990s.]]
Others were created because of [[Residential segregation|segregation]] imposed by the colonialists. For example, [[Dharavi|Dharavi slum of Mumbai]] – now one of the largest slums in [[India]], used to be a village referred to as Koliwadas, and Mumbai used to be referred as Bombay. In 1887, the British colonial government expelled all tanneries, other noxious industry and poor natives who worked in the peninsular part of the city and colonial housing area, to what was back then the northern fringe of the city – a settlement now called Dharavi. This settlement attracted no colonial supervision or investment in terms of road infrastructure, [[sanitation]], public services or housing. The poor moved into Dharavi, found work as servants in colonial offices and homes and in the foreign owned tanneries and other polluting industries near Dharavi. To live, the poor built shanty towns within easy commute to work. By 1947, the year India became an independent nation of the commonwealth, Dharavi had blossomed into Bombay's largest slum.<ref name="jn2010">Jan Nijman (February 2010). "A Study of Space in Mumbai's Slums". ''Tijdschrift voor economische en sociale geografie''. Volume 101, Issue 1, pages 4–17.</ref>

Similarly, some of the slums of [[Lagos]], Nigeria sprouted because of neglect and policies of the colonial era.<ref>Liora Bigon, "Between Local and Colonial Perceptions: The History of Slum Clearances in Lagos" (Nigeria), 1924–1960, ''African and Asian Studies'', Volume 7, Number 1, 2008, pages 49–76 (28)</ref> During apartheid era of [[South Africa]], under the pretext of sanitation and plague epidemic prevention, racial and ethnic group segregation was pursued, people of colour were moved to the fringes of the city, policies that created Soweto and other slums – officially called townships.<ref>Beinart, W., & Dubow, S. (Eds.), (2013), ''Segregation and apartheid in twentieth century South Africa'', Routledge, pages 25–35</ref> Large slums started at the fringes of segregation-conscious colonial city centers of Latin America.<ref>Griffin, E., and Ford, L. (1980). "A model of Latin American city structure". ''Geographical Review''. pages 397–422.</ref> Marcuse suggests ghettoes in the United States, and elsewhere, have been created and maintained by the segregationist policies of the state and regionally dominant group.<ref>Marcuse, Peter (2001), [http://www.urbancentre.utoronto.ca/pdfs/curp/Marcuse_Segregationandthe.pdf "Enclaves yes, ghettoes, no: Segregation and the state"] {{Webarchive|url=https://web.archive.org/web/20130921060842/http://www.urbancentre.utoronto.ca/pdfs/curp/Marcuse_Segregationandthe.pdf |date=2013-09-21}}, Lincoln Institute of Land Policy Conference Paper, Columbia University</ref><ref>Bauman, John F (1987). ''Public Housing, Race, and Renewal: Urban Planning in Philadelphia, 1920–1974''. Philadelphia: Temple University Press.</ref>{{page needed|date=October 2024}}

[[File:Makoko auf dem Wasser (5209071096).jpg|thumb|[[Makoko]] – One of the oldest slums in Nigeria, was originally a fishing [[village]] settlement, built on stilts on a lagoon. It developed into a slum and became home to about a hundred thousand people in [[Lagos]]. In 2012, it was partially destroyed by the city government, amidst controversy, to accommodate infrastructure for the city's growing population.<ref>[https://www.economist.com/middle-east-and-africa/2012/08/18/destroying-makoko "Destroying Makoko"]  ''The Economist'' (August 18, 2012)</ref>]]

===Poor infrastructure, social exclusion and economic stagnation===
[[Social exclusion]] and poor infrastructure forces the poor to adapt to conditions beyond his or her control. Poor families that cannot afford transportation, or those who simply lack any form of affordable public transportation, generally end up in squat settlements within walking distance or close enough to the place of their formal or informal employment.<ref name="lse" /> Ben Arimah cites this social exclusion and poor infrastructure as a cause for numerous slums in African cities.<ref name="barimslum">[http://www.oecd.org/dev/pgd/46837274.pdf "Slums as Expressions of Social Exclusion: Explaining the Prevalence of Slums in African Countries"] {{Webarchive|url=https://web.archive.org/web/20131015175604/http://www.oecd.org/dev/pgd/46837274.pdf |date=2013-10-15}} Ben Arimah, United Nations Human Settlements Programme, Nairobi, Kenya</ref> Poor quality, unpaved streets encourage slums; a 1% increase in paved all-season roads, claims Arimah, reduces slum incidence rate by about 0.35%. Affordable public transport and economic infrastructure empowers poor people to move and consider housing options other than their current slums.<ref>[http://www.irinnews.org/report/84803/africa-improved-infrastructure-key-to-slum-upgrading-un-official "Africa: Improved infrastructure key to slum upgrading – UN Official"] {{Webarchive|url=https://web.archive.org/web/20131021025838/http://www.irinnews.org/report/84803/africa-improved-infrastructure-key-to-slum-upgrading-un-official |date=2013-10-21}} IRIN, United Nations News Service (June 11, 2009)</ref><ref>[http://www.gsd.harvard.edu/academic/fellowships/wheelwright/images/Slum%20Upgrading_Elisa%20Silva.pdf "Latin American Slum Upgrading Efforts"] {{Webarchive|url=https://web.archive.org/web/20131021081502/http://www.gsd.harvard.edu/academic/fellowships/wheelwright/images/Slum%20Upgrading_Elisa%20Silva.pdf |date=2013-10-21}} Elisa Silva, Arthur Wheelwright Traveling Fellowship 2011, Harvard University</ref>

A growing economy that creates jobs at rate faster than population growth, offers people opportunities and incentive to relocate from poor slum to more developed neighborhoods. Economic stagnation, in contrast, creates uncertainties and risks for the poor, encouraging people to stay in the slums. Economic stagnation in a nation with a growing population reduces per capita disposal income in urban and rural areas, increasing urban and rural poverty. Rising rural poverty also encourages migration to urban areas. A poorly performing economy, in other words, increases poverty and rural-to-urban migration, thereby increasing slums.<ref>[http://www.unhabitat.org/pmss/listItemDetails.aspx?publicationID=1156 "The Challenge of Slums: Global Report on Human Settlements" (2003)] {{Webarchive|url=https://web.archive.org/web/20140111041647/http://www.unhabitat.org/pmss/listItemDetails.aspx?publicationID=1156 |date=2014-01-11}}, United Nations Human Settlements Programme; {{ISBN|1-84407-037-9}}</ref><ref name="globalurban.org">[http://www.globalurban.org/GUDMag06Vol2Iss1/Kuiper%20&%20van%20der%20Ree.htm "Growing out of poverty: Urban job Creation and the Millennium Development Goals"] {{Webarchive|url=https://web.archive.org/web/20191031182019/http://www.globalurban.org/GUDMag06Vol2Iss1/Kuiper%20%26%20van%20der%20Ree.htm |date=2019-10-31}} Marja Kuiper and Kees van der Ree, ''Global Urban Development Magazine'', Vol 2, Issue 1, March 2006</ref>

===Informal economy===
{{Main|Informal economy}}
Many slums grow because of growing informal economy which creates demand for workers. Informal economy is that part of an economy that is neither registered as a business nor licensed, one that does not pay taxes and is not monitored by local, state, or federal government.<ref>{{cite web |title=The Informal Economy: Fact Finding Study |url=http://rru.worldbank.org/Documents/PapersLinks/Sida.pdf |publisher=Department for Infrastructure and Economic Cooperation |access-date=November 20, 2011 |archive-url=https://web.archive.org/web/20111027063706/http://rru.worldbank.org/Documents/PapersLinks/Sida.pdf |archive-date=October 27, 2011}}</ref> Informal economy grows faster than formal economy when government laws and regulations are opaque and excessive, government bureaucracy is corrupt and abusive of entrepreneurs, labour laws are inflexible, or when law enforcement is poor.<ref>Dan Andrews, Aida Caldera Sánchez, and Åsa Johansson (May 30, 2011). [http://www.oecd-ilibrary.org/economics/towards-a-better-understanding-of-the-informal-economy_5kgb1mf88x28-en "Towards a better understanding of informal economy"] {{Webarchive|url=https://web.archive.org/web/20150109045139/http://www.oecd-ilibrary.org/economics/towards-a-better-understanding-of-the-informal-economy_5kgb1mf88x28-en |date=2015-01-09}}. OECD France.</ref> Urban informal sector is between 20 and 60% of most developing economies' GDP; in Kenya, 78 per cent of non-agricultural employment is in the informal sector making up 42 per cent of GDP.<ref name="whyslums" /> In many cities the informal sector accounts for as much as 60 per cent of employment of the urban population. For example, in Benin, slum dwellers comprise 75 per cent of informal sector workers, while in Burkina Faso, the Central African Republic, Chad and Ethiopia, they make up 90 per cent of the informal labour force.<ref>[http://www.unhabitat.org/downloads/docs/3974_95355_A%20Fact%20Sheet%20on%20UN-HABITAT%20and%20Youth%20sr%20Oct%2026.doc "The state of world's cities"] {{Webarchive|url=https://web.archive.org/web/20090704145004/http://www.unhabitat.org/downloads/docs/3974_95355_A%20Fact%20Sheet%20on%20UN-HABITAT%20and%20Youth%20sr%20Oct%2026.doc |date=2009-07-04}} UN Habitat (2007)</ref> Slums thus create an informal alternate economic ecosystem, that demands low paid flexible workers, something impoverished residents of slums deliver. In other words, countries where starting, registering and running a formal business is difficult, tend to encourage informal businesses and slums.<ref>Geoffrey Nwaka (May 2005). [http://www.globalurban.org/Issue1PIMag05/NWAKA%20article.htm "The Urban Informal Sector in Nigeria"] {{Webarchive|url=https://web.archive.org/web/20130913160353/http://www.globalurban.org/Issue1PIMag05/NWAKA%20article.htm |date=2013-09-13}}. ''Global Urban Development Magazine''. Vol 1, No 1.</ref><ref>Sam Sturgis (January 3, 2013). [http://nextcity.org/informalcity/entry/in-nairobis-slums-potential-and-problems-as-big-as-africa-itself "In nairobi's slums, problems and potential as big as Africa itself"] {{Webarchive|url=https://web.archive.org/web/20150109002105/http://nextcity.org/informalcity/entry/in-nairobis-slums-potential-and-problems-as-big-as-africa-itself |date=2015-01-09}}. Rockefeller Foundation.</ref><ref>Jim Yardley (December 28, 2011). [https://www.nytimes.com/2011/12/29/world/asia/in-indian-slum-misery-work-politics-and-hope.html?pagewanted=all&_r=0 "In one slum, misery, work, politics and hope"] {{Webarchive|url=https://web.archive.org/web/20150108233014/http://www.nytimes.com/2011/12/29/world/asia/in-indian-slum-misery-work-politics-and-hope.html?pagewanted=all&_r=0 |date=2015-01-08}} ''The New York Times''.</ref> Without a sustainable formal economy that raise incomes and create opportunities, squalid slums are likely to continue.<ref>Minnery et al., "Slum upgrading and urban governance: Case studies in three South East Asian cities", ''Habitat International'', Volume 39, July 2013, Pages 162–169.</ref>

[[File:Ramos Arizpe slums.jpg|thumb|A slum near [[Ramos Arizpe]] in [[Mexico]].]]
The World Bank and UN Habitat estimate, assuming no major economic reforms are undertaken, more than 80% of additional jobs in urban areas of developing world may be low-paying jobs in the informal sector. Everything else remaining same, this explosive growth in the informal sector is likely to be accompanied by a rapid growth of slums.<ref name="whyslums" />

=== Labour, work ===

Research in the latest years based on ethnographic studies, conducted since 2008 about slums, published initially in 2017, has found out the primary importance of labour as the main cause of emergence, rural-urban migration, consolidation and growth of informal settlements.<ref name="Cavalcanti">{{Cite book |url=https://books.google.com/books?id=jrCfugEACAAJ |title=Housing Shaped by Labour: The Architecture of Scarcity in Informal Settlements |last=Cavalcanti |first=Ana Rosa Chagas |date=November 2018 |publisher=Jovis Verlag GmbH |isbn=978-3-86859-534-5}}</ref>{{page needed|date=October 2024}}<ref name="CAVALCANTI 2017 71–81">{{Cite journal |last=Cavalcanti |first=Ana Rosa Chagas |date=2017|title=Work, Slums, and Informal Settlement Traditions: Architecture of the Favela Do Telegrafo |journal=Traditional Dwellings and Settlements Review |volume=28 |issue=2 |pages=71–81 |issn=1050-2092 |jstor=44779812}}</ref> It also showed that work has also a crucial role in the self-construction of houses, alleys and overall informal planning of slums, as well as constituting a central aspect by residents living in slums when their communities suffer upgrading schemes or when they are resettled to formal housing.<ref name="Cavalcanti" />{{page needed|date=October 2024}}

For example, it was recently proved that in a small favela in the northeast of Brazil (Favela Sururu de Capote), the migration of dismissed sugar cane factory workers to the city of Maceió (who initiated the self-construction of the favela), has been driven by the necessity to find a job in the city.<ref name="CAVALCANTI 2017 71–81" /> The same observation was noticed on the new migrants who contribute to the consolidation and growth of the slum. Also, the choice of the terrain for the construction of the favela (the margins of a lagoon) followed the rationale that it could offer conditions to provide them means of work. Circa 80% of residents living in that community live from the fishery of a mussel which divides the community through gender and age.<ref name="CAVALCANTI 2017 71–81" /> Alleys and houses were planned to facilitate the working activities, that provided subsistence and livelihood to the community. When resettled, the main reason of changes of formal housing units was due to the lack of possibilities to perform their work in the new houses designed according to formal architecture principles, or even by the distances they had to travel to work in the slum where they originally lived, which was in turn faced by residents by self-constructing spaces to shelter the work originally performed in the slum, in the formal housing units.<ref name="Cavalcanti" />{{page needed|date=October 2024}} Similar observations were made in other slums.<ref name="Cavalcanti" />{{page needed|date=October 2024}} Residents also reported that their work constitutes their dignity, citizenship, and self-esteem in the underprivileged settings in which they live.<ref name="Cavalcanti" />{{page needed|date=October 2024}} The reflection of this recent research was possible due to participatory observations and the fact that the author of the research has lived in a slum to verify the socioeconomic practices which were prone to shape, plan and govern space in slums.<ref name="Cavalcanti" />{{page needed|date=October 2024}}

===Poverty===
{{Main|Poverty}}
Urban poverty encourages the formation and demand for slums.<ref name="UN-Habitat 2007 Press Release" /> With rapid shift from rural to urban life, poverty migrates to urban areas. The urban poor arrives with hope, and very little of anything else. They typically have no access to shelter, basic urban services and social amenities. Slums are often the only option for the urban poor.<ref>''Slums of the World: The Face of Urban Poverty in the New Millennium?'' {{ISBN|92-1-131683-9}}, UN-Habitat</ref>{{page needed|date=October 2024}}
[[File:Slum shower jbi.jpg|thumb|A woman from a slum is taking a bath in a river.]]

===Politics===
Many local and national governments have, for political interests, subverted efforts to remove, reduce or upgrade slums into better housing options for the poor.<ref name="grhs2011">[http://www.unhabitat.org/downloads/docs/GRHS.2003.2.pdf "Assessing Slums in the Development Context"] {{Webarchive|url=https://web.archive.org/web/20140105025237/http://www.unhabitat.org/downloads/docs/GRHS.2003.2.pdf |date=2014-01-05}} United Nations Habitat Group (2011)</ref> Throughout the second half of the 19th century, for example, French political parties relied on votes from slum population and had vested interests in maintaining that voting block. Removal and replacement of slum created a conflict of interest, and politics prevented efforts to remove, relocate or upgrade the slums into housing projects that are better than the slums. Similar dynamics are cited in favelas of Brazil,<ref>[http://www.ucl.ac.uk/dpu-projects/Global_Report/pdfs/SaoPaulo.pdf "The case of São Paulo, Brazil – Slums"] {{Webarchive|url=https://web.archive.org/web/20160306145657/http://www.ucl.ac.uk/dpu-projects/Global_Report/pdfs/SaoPaulo.pdf |date=2016-03-06}} Mariana Fix, Pedro Arantes and Giselle Tanaka, Laboratorio de Assentamentos Humanos de FAU-USP, São Paulo, pages 15–20</ref> slums of India,<ref>Philip Reeves (May 9, 2007). [https://www.npr.org/templates/story/story.php?storyId=10089935 "Bid to develop Indian slum draws opposition"] {{Webarchive|url=https://web.archive.org/web/20181106232912/https://www.npr.org/templates/story/story.php?storyId=10089935 |date=2018-11-06}} NPR (Washington D.C.).</ref><ref name="Slum banged">Joshi and Unnithan (March 7, 2005). [http://indiatoday.intoday.in/story/vote-bank-politics-cm-vilasrao-deshmukh-halts-mumbai-slum-demolition-drive/1/194322.html "Slum banged"] {{Webarchive|url=https://web.archive.org/web/20140808053058/http://indiatoday.intoday.in/story/vote-bank-politics-cm-vilasrao-deshmukh-halts-mumbai-slum-demolition-drive/1/194322.html |date=2014-08-08}} ''India Today''.</ref> and shanty towns of Kenya.<ref>Irene Wangari Karanja and Jack Makau (2010). [http://www.irinnews.org/pdf/nairobi_inventory.pdf "Inventory of the Slums in Nairobi"] {{Webarchive|url=https://web.archive.org/web/20130810022349/http://www.irinnews.org/pdf/nairobi_inventory.pdf |date=2013-08-10}} IRIN, United Nations News Service. page 10–14.</ref>

[[File:Principaux Bidonvilles.png|thumb|The location of 100 largest "contiguous" mega-slums in the world. Numerous other regions have slums, but those slums are scattered. The numbers show population in millions per mega-slum, the initials are derived from city name. Some of the largest slums of the world are in areas of political or social conflicts.]]
Scholars<ref name="grhs2011" /><ref>Gerald Suttles (1970). ''The Social Order of the Slum: Ethnicity and Territory in the Inner City''. {{ISBN|978-0226781921}}. University of Chicago Press. Chapter 1.</ref> claim politics also drives rural-urban migration and subsequent settlement patterns. Pre-existing patronage networks, sometimes in the form of gangs and other times in the form of political parties or social activists, inside slums seek to maintain their economic, social and political power. These social and political groups have vested interests to encourage migration by ethnic groups that will help maintain the slums, and reject alternate housing options even if the alternate options are better in every aspect than the slums they seek to replace.<ref name="Slum banged" /><ref>Ahsan Ullah (2002). [http://iussp2005.princeton.edu/papers/50712 "Bright City Lights and Slums of Dhaka city"] {{Webarchive|url=https://web.archive.org/web/20130507043643/http://iussp2005.princeton.edu/papers/50712 |date=2013-05-07}} City University of Hong Kong.</ref>

===Social conflicts===
Millions of [[Lebanon|Lebanese]] people formed slums during the [[Lebanese Civil War]] from 1975 to 1990.<ref>[http://www.unhabitat.org/downloads/docs/GRHS.2003.4.pdf "Slums – Summary of City Case Studies"] {{Webarchive|url=https://web.archive.org/web/20130921055646/http://www.unhabitat.org/downloads/docs/GRHS.2003.4.pdf |date=2013-09-21}} UN Habitat, page 203.</ref><ref>Mona Fawaz and Isabelle Peillen (2003). [http://www.ucl.ac.uk/dpu-projects/Global_Report/pdfs/Beirut.pdf "Slums: The case of Beirut, Lebanon"] {{Webarchive|url=https://web.archive.org/web/20130921060855/http://www.ucl.ac.uk/dpu-projects/Global_Report/pdfs/Beirut.pdf |date=2013-09-21}}, Massachusetts Institute of Technology.</ref> Similarly, in recent years, numerous slums have sprung around Kabul to accommodate rural Afghans escaping Taliban violence.<ref>[https://www.amnesty.org/en/documents/asa11/001/2012/en/ "Fleeing war, finding misery: The plight of the internally displaced in Afghanistan"] {{Webarchive|url=https://web.archive.org/web/20181122054838/https://www.amnesty.org/en/documents/asa11/001/2012/en/ |date=2018-11-22}} Amnesty International (February 2012); pages 9–12</ref>

===Natural disasters===
Major natural disasters in poor nations often lead to migration of disaster-affected families from areas crippled by the disaster to unaffected areas, the creation of temporary tent city and slums, or expansion of existing slums.<ref>[http://www.citiesalliance.org/About-slum-upgrading "Slum upgrading – Why do slums develop"] {{Webarchive|url=https://web.archive.org/web/20130906160759/https://www.citiesalliance.org/About-slum-upgrading |date=2013-09-06}} Cities Alliance (2011)</ref> These slums tend to become permanent because the residents do not want to leave, as in the case of slums near Port-au-Prince after the [[2010 Haiti earthquake]],<ref>[http://www.miamiherald.com/2013/01/08/3173715/three-years-after-haiti-earthquake.html "Three years after Haiti earthquake, loss of hope, desperation"] {{Webarchive|url=https://web.archive.org/web/20131003100844/http://www.miamiherald.com/2013/01/08/3173715/three-years-after-haiti-earthquake.html |date=2013-10-03}} Jacqueline Charles, ''Miami Herald'' (January 8, 2013)</ref><ref>[https://www.telegraph.co.uk/news/worldnews/centralamericaandthecaribbean/haiti/9425214/Slum-eviction-plans-in-Haiti-spark-protests.html "Slum eviction plans in Haiti spark protests"] {{Webarchive|url=https://web.archive.org/web/20181103004246/https://www.telegraph.co.uk/news/worldnews/centralamericaandthecaribbean/haiti/9425214/Slum-eviction-plans-in-Haiti-spark-protests.html |date=2018-11-03}} ''The Telegraph'' (United Kingdom), July 25, 2012</ref> and slums near Dhaka after 2007 [[Bangladesh]] Cyclone [[Cyclone Sidr|Sidr]].<ref>[http://reliefweb.int/report/bangladesh/bangladesh-cyclone-rebuilding-after-cyclone-sidr Bangladesh cyclone: Rebuilding after Cyclone Sidr] {{Webarchive|url=https://web.archive.org/web/20160304073813/http://reliefweb.int/report/bangladesh/bangladesh-cyclone-rebuilding-after-cyclone-sidr |date=2016-03-04}} Habitat for Humanity International (May 6, 2009)</ref>

==Slums in developing countries==
[[File:Shanty housing in Hong Kong.jpeg|thumb|Slum in [[Tai Hang]], Hong Kong, in the 1990s]]

===Location and growth===
Slums typically begin at the outskirts of a city. Over time, the city may expand past the original slums, enclosing the slums inside the urban perimeter. New slums sprout at the new boundaries of the expanding city, usually on publicly owned lands, thereby creating an [[urban sprawl]] mix of formal settlements, industry, retail zones and slums. This makes the original slums valuable property, densely populated with many conveniences attractive to the poor.<ref name="rff">Rosa Flores Fernandez (2011), [http://halshs.archives-ouvertes.fr/docs/00/75/16/70/PDF/1._Rosa_Flores_Fernandez_-_VULNERABLE_SLUM_CHARACTERISTICS.pdf "Physical and Spatial Characteristics of Slum Territories Vulnerable to Natural Disasters"] {{Webarchive|url=https://web.archive.org/web/20131020234757/http://halshs.archives-ouvertes.fr/docs/00/75/16/70/PDF/1._Rosa_Flores_Fernandez_-_VULNERABLE_SLUM_CHARACTERISTICS.pdf |date=2013-10-20}}, Les Cahiers d'Afrique de l'Est, n° 44, French Institute for Research in Africa</ref>

At their start, slums are typically located in the least desirable lands near the town or city, that are state owned, are part of a philanthropic trust, possessed by a religious entity, or have no clear land title. In cities located in mountainous terrain, slums begin on difficult to reach slopes or start at the bottom of flood prone valleys, often hidden from the plain view of downtown but close to some natural water source.<ref name="rff" /> In cities located near lagoons, marshlands and rivers, they start on banks or on stilts above water or the dry river bed; in flat terrain, slums begin on lands unsuitable for agriculture, near city trash dumps, next to railway tracks,<ref name="dspace.cigilibrary.org">Banerji, M. (2009), [https://web.archive.org/web/20131021010910/http://dspace.cigilibrary.org/jspui/bitstream/123456789/21075/1/Provision%20of%20Basic%20Services%20in%20the%20Slums%20and%20Resettlement%20Colonies%20of%20Delhi.pdf?1 "Provision of basic services in the slums and resettlement colonies of Delhi"], Institute of Social Studies Trust</ref> and other shunned undesirable locations.

These strategies shield slums from the risk of being noticed and removed when they are small and most vulnerable to local government officials. Initial homes tend to be tents and shacks that are quick to install, but as a slum grows, becomes established and newcomers pay the informal association or gang for the right to live in the slum, the construction materials for the slums switches to more durable materials such as bricks and concrete, suitable for slum's topography.<ref>Lloyd, P. (1979), ''Slums of Hope: shanty towns of the Third World'', Manchester University Press, {{ISBN|978-0719007071}}</ref>{{page needed|date=October 2024}}<ref>McAuslan, Patrick. (1986). ''Les mal logés du Tiers-Monde''. Paris: Éditions L'Harmattan</ref>{{page needed|date=October 2024}}

The original slums, over time, get established next to centers of economic activity, schools, hospitals, and sources of employment, which the poor rely on.<ref name="Cavalcanti" />{{page needed|date=October 2024}} Established old slums, surrounded by the formal city infrastructure, cannot expand horizontally; therefore, they grow vertically by stacking additional rooms, sometimes for a growing family and sometimes as a source of rent from new arrivals in slums.<ref>Centre des Nations Unies pour les Etablissements Humains (CNUEH). (1981). [https://www.worldcat.org/oclc/799133434 "Amélioration physique des taudis et des bidonvilles"] {{Webarchive|url=https://web.archive.org/web/20141101223747/http://www.worldcat.org/title/amelioration-physique-des-taudis-et-des-bidonvilles-rapport-dune-reunion/oclc/799133434 |date=2014-11-01}}, Nairobi</ref> Some slums name themselves after founders of political parties, locally respected historical figures, current politicians or a politician's spouse to garner political backing against eviction.<ref>Gilbert, Daniel (1990), ''Barriada Haute-Espérance : Récit d'une coopération au Pérou''. Paris: Éditions Karthala</ref>{{page needed|date=October 2024}}

===Insecure tenure===
Informality of [[land tenure]] is a key characteristic of urban slums.<ref name="whyslums" /> At their start, slums are typically located in undesirable lands near the town or city, that are state owned or philanthropic trust owned or religious entity owned or have no clear land title.<ref name="rff" /> Some immigrants regard unoccupied land as land without owners and therefore occupy it.<ref name="etc">{{cite journal |last=Agbola |first=Tunde |author2=Elijah M. Agunbiade |title=Urbanization, Slum Development and Security of Tenure- The Challenges of Meeting Millennium Development Goal 7 in Metropolitan Lagos, Nigeria. |journal=Urban Population–Development–Environment Dynamics in the Developing World- Case Studies and Lessons Learned |year=2009 |pages=77–106}}</ref> In some cases the local community or the government allots lands to people, which will later develop into slums and over which the dwellers don't have [[property rights]].<ref name="Bolay" /> Informal land tenure also includes occupation of land belonging to someone else.<ref>* {{cite journal |last=Brueckner |first=Jan K. |author2=Harris Selod |title=A theory of urban squatting and land-tenure formalization in developing countries |journal=American Economic Journal: Economic Policy |volume=1 |year=2009 |pages=28–51 |doi=10.1257/pol.1.1.28 |s2cid=5261443 |url=https://www.economics.uci.edu/files/docs/workingpapers/2007-08/brueckner-16.pdf |access-date=2019-07-10 |archive-url=https://web.archive.org/web/20170810161520/http://www.economics.uci.edu/files/docs/workingpapers/2007-08/brueckner-16.pdf |archive-date=2017-08-10 |url-status=live}}
* {{cite journal |last=Davy |first=Ben |author2=Sony Pellissery |title=The citizenship promise (un) fulfilled: The [[right to housing]] in informal settings. |journal=International Journal of Social Welfare |year=2013 |volume=22 |issue=S1 |pages=68–84 |doi=10.1111/ijsw.12033}}</ref> According to Flood,{{who|date=August 2020}} 51 percent of slums are based on invasion of private land in [[sub-Saharan Africa]], 39 percent in [[North Africa]] and [[West Asia]], 10 percent in South Asia, 40 percent in [[East Asia]], and 40 percent in [[Latin America and the Caribbean]].<ref>{{cite journal |last=Flood |first=Joe |title=Secure Tenure Survey Final Report |journal=Urban Growth Management Initiative |year=2006}}</ref> In some cases, once the slum has many residents, the early residents form a social group, an informal association or a gang that controls newcomers, charges a fee for the right to live in the slums, and dictates where and how new homes get built within the slum. The newcomers, having paid for the right, feel they have commercial right to the home in that slum.<ref name="rff" /><ref>Taschner, Suzana (2001), "Desenhando os espaços da pobreza". Faculdade de Arquitetura e Urbanismo, Université de Sao Paulo.</ref> The slum dwellings, built as the slum grows, are constructed without checking land ownership rights or building codes, are not registered with the city, and often not recognized by the city or state governments.<ref>{{cite journal |last1=Field |first1=E |year=2005 |title=Property rights and investment in urban slums |journal=Journal of the European Economic Association |volume=3 |issue=2–3 |pages=279–290 |doi=10.1162/jeea.2005.3.2-3.279 |citeseerx=10.1.1.576.1330}}</ref><ref>{{cite journal |last1=Davis |first1=M |year=2006 |title=Planet of slums |journal=New Perspectives Quarterly |volume=23 |issue=2 |pages=6–11 |doi=10.1111/j.1540-5842.2006.00797.x}}</ref>

Secure land tenure is important for slum dwellers as an authentic recognition of their residential status in urban areas. It also encourages them to upgrade their housing facilities, which will give them protection against natural and unnatural hazards.<ref name="Bolay" /> Undocumented ownership with no [[legal title]] to the land also prevents slum settlers from applying for [[mortgage]], which might worsen their financial situations. In addition, without registration of the land ownership, the government has difficulty in upgrading basic facilities and improving the living environment.<ref name="etc" /> Insecure tenure of the slum, as well as a lack of socially and politically acceptable alternatives to slums, also creates difficulty in citywide [[infrastructure]] development such as rapid mass transit, electrical and sewer pipe layout, highways and roads.<ref>Ravetz, A. (2013). ''The government of space: town planning in modern society''. Routledge.</ref>{{page needed|date=October 2024}}

===Substandard housing and overcrowding===
[[File:09874jfCity Rizal Avenue School Manila Streets Landmarksfvf 07.JPG|thumb|Substandard housing in a slum in [[Manila]], Philippines in the 2000s.]]
Slum areas are characterized by substandard housing structures.<ref>{{cite journal |doi=10.2307/3159005 |jstor=3159005 |title=Filtering down and the Elimination of Substandard Housing |journal=The Journal of Land & Public Utility Economics |volume=21 |issue=4 |pages=322–330 |last1=Ratcliff |first1=Richard U. |year=1945}}</ref><ref>{{cite journal |doi=10.1080/01944366508978170 |title=Housing Policy Goals and the Turnover of Housing |journal=Journal of the American Institute of Planners |volume=31 |issue=3 |pages=232–245 |year=1965 |last1=Kristof |first1=Frank S.}}</ref> Shanty homes are often built hurriedly, on ad hoc basis, with materials unsuitable for housing. Often the construction quality is inadequate to withstand heavy rains, high winds, or other local climate and location. Paper, plastic, earthen floors, mud-and-wattle walls, wood held together by ropes, straw or torn metal pieces as roofs are some of the materials of construction. In some cases, brick and cement is used, but without attention to proper design and structural engineering requirements.<ref>{{cite journal |doi=10.2307/1287349 |jstor=1287349 |title=Housing Codes, Building Demolition, and Just Compensation: A Rationale for the Exercise of Public Powers over Slum Housing |journal=Michigan Law Review |volume=67 |issue=4 |pages=635–678 |last1=Mandelker |first1=Daniel R. |year=1969 |url=https://repository.law.umich.edu/mlr/vol67/iss4/2|url-access=subscription }}</ref> Various space, dwelling placement bylaws and local building codes may also be extensively violated.<ref name="UN-Habitat 2007 Press Release" /><ref>United Nations Human Settlements Programme, ''The challenge of slums: global report on human settlements'' 2003, London and Sterling, Earthscan Publications Ltd; 2003; {{ISBN|1-84407-037-9}}</ref>{{page needed|date=October 2018}}

Overcrowding is another characteristic of slums. Many dwellings are single room units, with high occupancy rates. Each dwelling may be cohabited by multiple families. Five and more persons may share a one-room unit; the room is used for cooking, sleeping and living. Overcrowding is also seen near sources of drinking water, cleaning, and sanitation where one toilet may serve dozens of families.<ref>{{cite journal |doi=10.1007/s11524-007-9199-x |pmid=17551841 |pmc=2134844 |title=Quality of Water the Slum Dwellers Use: The Case of a Kenyan Slum |journal=Journal of Urban Health |volume=84 |issue=6 |pages=829–838 |year=2007 |last1=Kimani-Murage |first1=Elizabeth Wambui |last2=Ngindu |first2=Augustine M.}}</ref><ref>{{cite journal |doi=10.1080/02665438808725650 |title='Unhealthy areas': Town planning, eugenics and the slums, 1890–1945 |journal=Planning Perspectives |volume=3 |pages=24–46 |year=2007 |last1=Garside |first1=Patrica L.}}</ref><ref>Wohl, A. S. (1977). ''The Eternal Slum: Housing and Social Policy in Victorian'' (Vol. 5). Transaction Books.</ref>{{page needed|date=October 2024}} In a slum of Kolkata, India, over 10 people sometimes share a 45 m<sup>2</sup> room.<ref>Kundu N (2003) "Urban slum reports: The case of Kolkata, India". Nairobi: United Nations.</ref> In Kibera slum of Nairobi, Kenya, population density is estimated at 2,000 people per hectare — or about 500,000 people in one square mile.<ref>[http://www.unhabitat.org/content.asp?cid=3220&catid=206&typeid=13 "Integrated Water Sanitation and Waste Management in Kibera"] {{Webarchive|url=https://web.archive.org/web/20131004230218/http://www.unhabitat.org/content.asp?cid=3220&catid=206&typeid=13 |date=2013-10-04}} United Nations (2008)</ref>

However, the density and [[neighbourhood effects]] of slum populations may also offer an opportunity to target health interventions.<ref name="pmid27760702">{{cite journal |doi=10.1016/S0140-6736(16)31848-7 |pmid=27760702 |title=Improving the health and welfare of people who live in slums |journal=The Lancet |volume=389 |issue=10068 |pages=559–570 |year=2017 |last1=Lilford |first1=Richard J. |last2=Oyebode |first2=Oyinlola |last3=Satterthwaite |first3=David |last4=Melendez-Torres |first4=G. J. |last5=Chen |first5=Yen-Fu |last6=Mberu |first6=Blessing |last7=Watson |first7=Samuel I. |last8=Sartori |first8=Jo |last9=Ndugwa |first9=Robert |last10=Caiaffa |first10=Waleska |last11=Haregu |first11=Tilahun |last12=Capon |first12=Anthony |last13=Saith |first13=Ruhi |last14=Ezeh |first14=Alex |s2cid=3511402 |url=http://wrap.warwick.ac.uk/83214/1/WRAP_Slum%20Health%20Paper%202-%20RESUBMISSION_FINALCOPY_CLEAN.pdf |access-date=2019-07-10 |archive-url=https://web.archive.org/web/20180719041445/http://wrap.warwick.ac.uk/83214/1/WRAP_Slum%20Health%20Paper%202-%20RESUBMISSION_FINALCOPY_CLEAN.pdf |archive-date=2018-07-19 |url-status=live}}</ref>

===Inadequate or no infrastructure===
[[File:Jakarta-slums-1975-IHS-10-Railway.JPG|thumb|Slum with tiled roofs and railway, Jakarta railway slum resettlement 1975, Indonesia.]]
One of the identifying characteristics of slums is the lack of or inadequate public infrastructure.<ref>[https://archive.today/20130918234806/http://www.unhabitat.org/content.asp?cid=668&catid=206&typeid=13 "Kenya Slum Upgrading Project"] United Nations Habitat (2011)</ref><ref>Cristina Iacoboaea (2009). [http://www.um.ase.ro/no10/9.pdf "Slums in Romania"] {{Webarchive|url=https://web.archive.org/web/20150610092733/http://www.um.ase.ro/no10/9.pdf |date=2015-06-10}}. ''TERUM'', No 1, Vol 10, pages 101–113.</ref> From safe drinking water to electricity, from basic health care to police services, from affordable public transport to fire/ambulance services, from sanitation sewer to paved roads, new slums usually lack all of these. Established, old slums sometimes garner official support and get some of these infrastructure such as paved roads and unreliable electricity or water supply.<ref>[http://www.archive-iussp.org/Activities/wgc-urb/chandrasekhar.pdf "Growth of Slums, Availability of Infrastructure and Demographic Outcomes in Slums: Evidence from India"]{{Dead link|date=May 2023 |bot=InternetArchiveBot |fix-attempted=yes}} S Chandrasekhar (2005), Urbanization in Developing Countries at the Population Association of America, Philadelphia</ref> Slums usually lack [[street address]]es, which creates further problems.<ref>[https://www.theguardian.com/news/2020/mar/26/the-unlisted-how-people-without-an-address-are-stripped-of-their-basic-rights "The unlisted: how people without an address are stripped of their basic rights"] {{Webarchive|url=https://web.archive.org/web/20200328092348/https://www.theguardian.com/news/2020/mar/26/the-unlisted-how-people-without-an-address-are-stripped-of-their-basic-rights |date=2020-03-28}} The Guardian, 2020</ref>

Slums often have very narrow alleys that do not allow vehicles (including [[emergency vehicles]]) to pass. The lack of services such as routine [[Waste collection|garbage collection]] allows rubbish to accumulate in huge quantities.<ref>{{Cite web|url=https://www.atcmask.com/blogs/blog/ghana-sodom-and-gomorrah|title=Sodom And Gomorrah (Agbogbloshie) - Ghana|last=Chasant|first=Muntaka|date=December 23, 2018|website=ATC MASK|access-date=February 19, 2019|archive-url=https://web.archive.org/web/20190219012413/https://www.atcmask.com/blogs/blog/ghana-sodom-and-gomorrah|archive-date=February 19, 2019|url-status=usurped}}</ref> The lack of infrastructure is caused by the informal nature of settlement and no planning for the poor by government officials. Fires are often a serious problem.<ref>Matt Birkinshaw, Abahlali baseMjondolo Movement SA (August 2008). [http://abahlali.org/files/Big_Devil_Politics_of_Shack_Fire.pdf "Big Devil in the Jondolos: The Politics of Shack Fires"]. {{Webarchive|url=https://web.archive.org/web/20110724213920/http://abahlali.org/files/Big_Devil_Politics_of_Shack_Fire.pdf |date=2011-07-24}}</ref>

In many countries, local and national government often refuse to recognize slums, because the slum are on disputed land, or because of the fear that quick official recognition will encourage more slum formation and seizure of land illegally. Recognizing and notifying slums often triggers a creation of property rights, and requires that the government provide public services and infrastructure to the slum residents.<ref>{{cite journal |doi=10.1177/0956247812456356 |pmid=23400338 |pmc=3565225 |title=Off the map: The health and social implications of being a non-notified slum in India |journal=Environment and Urbanization |volume=24 |issue=2 |pages=643–663 |year=2012 |last1=Subbaraman |first1=Ramnath |last2=o'Brien |first2=Jennifer |last3=Shitole |first3=Tejal |last4=Shitole |first4=Shrutika |last5=Sawant |first5=Kiran |last6=Bloom |first6=David E. |last7=Patil-Deshmukh |first7=Anita|bibcode=2012EnUrb..24..643S }}</ref><ref>{{cite journal |doi=10.1111/j.1467-9493.2012.00456.x |title=Regimes of spatial ordering in Brazil: Neoliberalism, leftist populism and modernist aesthetics in slum upgrading in Recife |journal=Singapore Journal of Tropical Geography |volume=33 |issue=2 |pages=157–170 |year=2012 |last1=Nuijten |first1=Monique |last2=Koster |first2=Martijn |last3=De Vries |first3=Pieter|bibcode=2012SJTG...33..157N }}</ref> With poverty and informal economy, slums do not generate tax revenues for the government and therefore tend to get minimal or slow attention. In other cases, the narrow and haphazard layout of slum streets, houses and substandard shacks, along with persistent threat of crime and violence against infrastructure workers, makes it difficult to layout reliable, safe, cost effective and efficient infrastructure. In yet others, the demand far exceeds the government bureaucracy's ability to deliver.<ref>{{cite report |doi=10.1596/1813-9450-5388 |title=Poverty, Living Conditions, and Infrastructure Access: A Comparison of Slums in Dakar, Johannesburg, and Nairobi |series=Policy Research Working Papers |year=2010 |last1=Talukdar |first1=Debabrata |last2=Jack |first2=Darby |last3=Gulyani |first3=Sumila |hdl=10986/3872 |s2cid=140581715 |url=http://www-wds.worldbank.org/external/default/WDSContentServer/WDSP/IB/2010/07/28/000158349_20100728143906/Rendered/PDF/WPS5388.pdf |hdl-access=free}}</ref><ref>{{cite journal |doi=10.1007/s11524-007-9167-5 |pmid=17387618 |pmc=1891640 |title=Urbanization and Slum Formation |journal=Journal of Urban Health |volume=84 |issue=3 Suppl |pages=27–34 |year=2007 |last1=Ooi |first1=Giok Ling |last2=Phua |first2=Kai Hong}}</ref>

Low [[socioeconomic status]] of its residents is another common characteristic attributed to slum residents.<ref>{{Cite web |url=http://www.cpc.unc.edu/measure/publications/tr-06-35 |title=Slums of Urban Bangladesh: Mapping and Census, 2005. |access-date=2012-09-05 |archive-url=https://web.archive.org/web/20130622145834/http://www.cpc.unc.edu/measure/publications/tr-06-35 |archive-date=2013-06-22 |url-status=live}}</ref>

==Problems==
===Vulnerability to natural and man-made hazards===
[[File: Vietnam 08 - 151 - houses over the canals (3186477231).jpg|thumb|Slums in the city of [[Chau Doc]], Vietnam over river Hậu (Mekong branch). These slums are on stilts to withstand routine floods which last 3 to 4 months every year.]]

Slums are often placed in areas vulnerable to natural disasters such as [[landslides]]<ref>[https://www.theguardian.com/world/2010/apr/08/rio-landslide-brazil "Rio slum landslide leaves hundreds dead"] {{Webarchive|url=https://web.archive.org/web/20170504063618/https://www.theguardian.com/world/2010/apr/08/rio-landslide-brazil |date=2017-05-04}} ''The Guardian'' (April 8, 2010).</ref> and [[floods]].<ref>Dilley, M. (2005). ''Natural disaster hotspots: a global risk analysis'' (Vol. 5). World Bank Publications</ref>{{page needed|date=October 2024}}<ref>Smith, Keith (2013). ''Environmental hazards: assessing risk and reducing disaster'', Routledge, {{ISBN|978-0415681056}}</ref>{{page needed|date=October 2018}} In cities located in mountainous terrain, slums begin on slopes difficult to reach or start at the bottom of flood-prone valleys, often hidden from plain view in the city center but close to some natural water source.<ref name="rff" /> In cities located near lagoons, [[marshlands]] and rivers, they start at banks or on stilts above water or the dry river bed; in flat terrain, slums begin on lands unsuitable for agriculture, near city trash dumps, next to railway tracks,<ref name="dspace.cigilibrary.org" /> and other shunned, undesirable locations. These strategies shield slums from the risk of being noticed and removed when they are small and most vulnerable to local government officials.<ref name="rff" /> However, the ad hoc construction, lack of quality control on building materials used, poor maintenance, and uncoordinated spatial design make them prone to extensive damage during [[earthquakes]] as well from decay.<ref>Wisner, B. (Ed.). (2004). ''At risk: natural hazards, people's vulnerability, and disasters''. Psychology Press, {{ISBN|978-0415252157}}</ref>{{page needed|date=October 2018}}<ref>{{cite journal |doi=10.1177/095624780001200208 |title=Cities, disasters and livelihoods |journal=Environment and Urbanization |volume=12 |issue=2 |pages=93–102 |year=2000 |last1=Sanderson |first1=D. |doi-access=free|bibcode=2000EnUrb..12...93S }}</ref> These risks will be intensified by climate change.<ref>{{cite journal |doi=10.1177/0956247811398604 |title=Ill-health and poverty: A literature review on health in informal settlements |journal=Environment and Urbanization |volume=23 |pages=123–155 |year=2011 |last1=Sverdlik |first1=Alice |issue=1 |bibcode=2011EnUrb..23..123S |s2cid=155074833}}</ref>

[[File:Haiti earthquake damage.jpg|thumb|A slum in [[Haiti]] damaged by 2010 earthquake. Slums are vulnerable to extensive damage and human fatalities from landslides, floods, earthquakes, fire, high winds and other severe weather.<ref name="Pelling, M. 2009">Pelling, M., & Wisner, B. (Eds.). (2009), ''Disaster risk reduction: Cases from urban Africa'', Earthscan Publishers (UK); {{ISBN|978-1-84407-556-0}}</ref>{{page needed|date=October 2018}}]]
Some slums risk [[man-made hazards]] such as toxic [[industry (economics)|industries]], [[traffic congestion]] and collapsing [[infrastructure]].<ref name="Davis" />{{page needed|date=October 2024}} [[Fires]] are another major risk to slums and its inhabitants,<ref>{{cite web |url=http://indiatoday.intoday.in/story/massive-fire-breaks-out-at-outer-delhi-slum/1/261934.html |title=3 dead as massive fire breaks out at outer Delhi slum |date=April 12, 2013 |access-date=July 23, 2015 |archive-url=https://web.archive.org/web/20150723214648/http://indiatoday.intoday.in/story/massive-fire-breaks-out-at-outer-delhi-slum/1/261934.html |archive-date=July 23, 2015 |url-status=live}}</ref><ref>{{cite web |url=http://photos.denverpost.com/2013/07/11/manila-slum-fire-financial-district-shantytown/#5 |title=Photos: Manila slum fire leaves more than 1,000 homeless |access-date=July 23, 2015 |date=2013-07-11 |archive-url=https://web.archive.org/web/20150723200254/http://photos.denverpost.com/2013/07/11/manila-slum-fire-financial-district-shantytown/#5 |archive-date=July 23, 2015 |url-status=live}}</ref> with streets often too narrow to allow proper and quick access to fire control trucks.<ref name="Pelling, M. 2009" />{{page needed|date=October 2024}}<ref>{{cite journal |doi=10.1016/S0264-2751(98)00020-1 |title=Structural adjustment, urban systems, and disaster vulnerability in developing countries |journal=Cities |volume=15 |issue=4 |pages=291–299 |year=1998 |last1=Hamza |first1=Mohamed |author2-link=Roger Zetter |last2=Zetter |first2=Roger}}</ref>

===Unemployment and informal economy===
Due to lack of skills and education as well as competitive job markets,<ref name="Gupta">{{cite journal |last=Gupta |first=Indrani |author2=Arup Mitra |title=Rural migrants and labour segmentation: Micro-level evidence from Delhi slums. |journal=Economic and Political Weekly |year=2002 |pages=163–168}}</ref> many slum dwellers face high rates of unemployment.<ref>[https://www.who.int/gho/urban_health/determinants/slum_residence_text/en/ "Slum residence"] {{Webarchive|url=https://web.archive.org/web/20131005001446/http://www.who.int/gho/urban_health/determinants/slum_residence_text/en/ |date=2013-10-05}} World Health Organization (2010)</ref> The limit of job opportunities causes many of them to employ themselves in the [[informal economy]], inside the slum or in developed urban areas near the slum. This can sometimes be licit informal economy or illicit informal economy without working contract or any social security. Some of them are seeking jobs at the same time and some of those will eventually find jobs in formal economies after gaining some professional skills in informal sectors.<ref name="Gupta" />

Examples of licit informal economy include street vending, household enterprises, product assembly and packaging, making garlands and embroideries, domestic work, shoe polishing or repair, driving [[Auto rickshaw|tuk-tuk]] or manual rickshaws, construction workers or manually driven logistics, and handicrafts production.<ref>[http://www.citiesalliance.org/sites/citiesalliance.org/files/CAFiles/Projects/Final_Annexure_20.pdf "Taj Ganj Slum Housing"] {{Webarchive|url=https://web.archive.org/web/20131127004625/http://www.citiesalliance.org/sites/citiesalliance.org/files/CAFiles/Projects/Final_Annexure_20.pdf |date=2013-11-27}}, Cities Alliance (2012)</ref><ref>[http://water.tkk.fi/English/wr/research/global/myth/10_Heinonen_Informal_Myths-of-Mekong.pdf "The hidden role of informal economy"] {{Webarchive|url=https://web.archive.org/web/20130921060618/http://water.tkk.fi/English/wr/research/global/myth/10_Heinonen_Informal_Myths-of-Mekong.pdf |date=2013-09-21}} Ulla Heinonen, Helsinki University of Technology, Finland (2008); {{ISBN|978-951-22-9102-1}}</ref><ref name="CAVALCANTI 2017 71–81" /> In some slums, people sort and recycle trash of different kinds (from household garbage to electronics) for a living – selling either the odd usable goods or stripping broken goods for parts or raw materials.<ref name="CAVALCANTI 2017 71–81" /> Typically these licit informal economies require the poor to regularly pay a bribe to local police and government officials.<ref>[http://www.ucl.ac.uk/dpu-projects/Global_Report/pdfs/Karachi.pdf "The case of Karachi, Pakistan"] {{Webarchive|url=https://web.archive.org/web/20110409160935/http://www.ucl.ac.uk/dpu-projects/Global_Report/pdfs/Karachi.pdf |date=2011-04-09}} Urban Slum Reports, A series on Slums of the World (2011). page 13.</ref>

[[File:SLUMS BREED CRIME. UNITED STATES HOUSING AUTHORITY - NARA - 515429.jpg|thumb|A propaganda poster linking slum to violence, used by US Housing Authority in the 1940s. City governments in the US created many such{{page needed|date=October 2018}}propaganda posters and launched a media campaign to gain citizen support for slum clearance and planned public housing.<ref>Mark Byrnes (November 2, 2011). [http://www.theatlanticcities.com/design/2011/11/public-housing-posters-new-york-city/407/#slide1 "How New York City Sold Public Housing"] {{Webarchive|url=https://web.archive.org/web/20130927190458/http://www.theatlanticcities.com/design/2011/11/public-housing-posters-new-york-city/407/#slide1 |date=2013-09-27}} ''The Atlantic''.</ref>]]
Examples of illicit informal economy include illegal substance and weapons trafficking, drug or moonshine/[[changaa]] production, [[prostitution]] and gambling – all sources of risks to the individual, families and society.<ref>[http://allafrica.com/stories/201301071790.html "Uganda: slum areas, posh pubs biggest drug hubs"] {{Webarchive|url=https://web.archive.org/web/20130921072001/http://allafrica.com/stories/201301071790.html |date=2013-09-21}} ''All Africa News'' (January 7, 2013)</ref><ref name="Economist">{{cite news |url=http://www.economist.com/research/articlesBySubject/displaystory.cfm?subjectid=348945&story_id=16018262 |title=African Moonshine: Kill Me Quickly |work=[[The Economist (magazine)|The Economist]] |date=2010-04-29}}</ref><ref>Larry Whiteaker (1997), ''Seduction, Prostitution, and Moral Reform in New York, 1830–1860'', {{ISBN|978-0815328735}}, page 29.</ref> Recent reports reflecting illicit informal economies include drug trade and distribution in Brazil's ''favelas'', production of fake goods in the ''colonías'' of Tijuana, smuggling in ''katchi abadis'' and slums of Karachi, or production of synthetic drugs in the ''townships'' of Johannesburg.<ref>[[Vanda Felbab-Brown]], [http://www.brookings.edu/~/media/research/files/papers/2011/12/05%20latin%20america%20slums%20felbabbrown/1205_latin_america_slums_felbabbrown "Bringing the State to the Slum: Confronting Organized Crime and Urban Violence in Latin America – Lessons for Law Enforcement and Policymakers"] {{Webarchive|url=https://web.archive.org/web/20140307081012/http://www.brookings.edu/~/media/research/files/papers/2011/12/05%20latin%20america%20slums%20felbabbrown/1205_latin_america_slums_felbabbrown |date=2014-03-07}} Brookings Institution (December 2011)</ref>

The slum-dwellers in informal economies run many risks. The informal sector, by its very nature, means income insecurity and lack of social mobility. There is also absence of legal contracts, protection of labour rights, regulations and bargaining power in informal employments.<ref>{{cite book |last=Breman |first=J. |title=The labouring poor in India: Patterns of exploitation, subordination, and exclusion |year=2003 |publisher=Oxford University Press |location=New Delhi}}</ref>{{page needed|date=October 2024}}

===Violence===
[[File:Kowloon Walled City - 1989 Aerial.jpg|thumb|From the 1940s to the 1990s, the [[Kowloon Walled City]] in Hong Kong was controlled by local [[Triad (organized crime)|triads]].]]
Some scholars suggest that crime is one of the main concerns in slums.<ref>{{cite journal |last=Kabiru |first=C. W. |title="Making It": understanding adolescent resilience in two informal settlements (Slums) in Nairobi, Kenya |journal=Child & Youth Services |year=2012 |volume=33 |issue=1 |pages=12–32 |doi=10.1080/0145935x.2012.665321 |pmid=24382935 |display-authors=etal |pmc=3874576}}</ref> Empirical data suggest crime rates are higher in some slums than in non-slums, with slum homicides alone reducing life expectancy of a resident in a Brazil slum by 7 years than for a resident in nearby non-slum.<ref name="grhs2003" /><ref name="In the Violent Favelas of Brazil">S Mehta (August 2013). [http://www.nybooks.com/articles/archives/2013/aug/15/violent-favelas-brazil/?pagination=false "In the Violent Favelas of Brazil"] {{Webarchive|url=https://web.archive.org/web/20130917114753/http://www.nybooks.com/articles/archives/2013/aug/15/violent-favelas-brazil/?pagination=false |date=2013-09-17}} ''The New York Review of Books''.</ref> In some countries like Venezuela, officials have sent in the military to control slum criminal [[violence]] involved with drugs and weapons.<ref>[https://news.yahoo.com/venezuelas-military-enters-high-crime-slums-155220352.html "Venezuela's military enters high crime slums"] {{Webarchive|url=https://web.archive.org/web/20160305142048/http://news.yahoo.com/venezuelas-military-enters-high-crime-slums-155220352.html |date=2016-03-05}} Karl Ritter, Associated Press (May 17, 2013)</ref> [[Rape]] is another serious issue related to crime in slums. In Nairobi slums, for example, one-fourth of all teenage girls are raped each year.<ref>{{cite news |last=Newar |first=Rachel |title=In Kenya, Where One in Four Women has Been Raped, Self Defense Training Makes a Difference |url=http://blogs.smithsonianmag.com/smartnews/2013/06/in-kenya-where-one-in-four-women-has-been-raped-self-defense-training-makes-a-difference/ |access-date=November 6, 2013 |newspaper=Smithsonian Magazine |date=June 14, 2013 |archive-url=https://archive.today/20131106155800/http://blogs.smithsonianmag.com/smartnews/2013/06/in-kenya-where-one-in-four-women-has-been-raped-self-defense-training-makes-a-difference/ |archive-date=November 6, 2013 |url-status=live}}</ref>

On the other hand, while UN-Habitat reports some slums are more exposed to [[crimes]] with higher crime rates (for instance, the traditional inner-city slums), crime is not the direct resultant of block layout in many slums. Rather crime is one of the symptoms of slum dwelling; thus slums consist of more victims than criminals.<ref name="grhs2003" /> Consequently, slums do not always have consistently high crime rates, as the worst crime rates exist in sectors maintaining influence of illicit economy—such as drug trafficking, brewing, [[prostitution]], and [[gambling]]. Often in such circumstances, multiple [[gangs]] fight for control over revenue.<ref>[http://www.irinnews.org/report/74687/global-urban-conflict-fighting-for-resources-in-the-slums Global: Urban conflict – fighting for resources in the slums] {{Webarchive|url=https://web.archive.org/web/20131105031737/http://www.irinnews.org/report/74687/global-urban-conflict-fighting-for-resources-in-the-slums |date=2013-11-05}} IRIN, United Nations News Service (October 8, 2007)</ref><ref name="Slater 2009">Josephine Slater (2009), "Naked Cities - Struggle in the Global Slums", ''Mute'', Volume 2, Issue 3, ISBN 0-9550664-3-3</ref>

Slum crime rate correlates with insufficient [[law enforcement]] and inadequate public [[policing]]. In main cities of developing countries, law enforcement lags behind urban growth and slum expansion. Often police can not reduce crime because, due to ineffective city planning and governance, slums set inefficient crime prevention system. Such problems is not primarily due to community indifference. Leads and information intelligence from slums are rare, streets are narrow and a potential death traps to patrol, and many in the slum community have an inherent distrust of authorities from fear ranging from eviction to collection on unpaid utility bills to general law and order.<ref>[http://www.brookings.edu/research/papers/2011/12/05-latin-america-slums-felbabbrown "Bringing the State to the Slum: Confronting Organized Crime and Urban Violence in Latin America"] {{Webarchive|url=https://web.archive.org/web/20131005035149/http://www.brookings.edu/research/papers/2011/12/05-latin-america-slums-felbabbrown |date=2013-10-05}} Vanda Felbab-Brown (2011), Brookings Institution</ref> Lack of formal recognition by the governments also leads to few formal policing and public justice institutions in slums.<ref name="grhs2003" />

Women in slums are at greater risk of physical and [[sexual violence]].<ref name="ViolencenHIV">{{cite journal |last=Go |first=Vivian F. |title=When HIV-prevention messages and gender norms clash: the impact of domestic violence on women's HIV risk in slums of Chennai, India |journal=AIDS and Behavior |year=2003 |volume=7 |issue=3 |pages=263–272 |display-authors=etal |doi=10.1023/A:1025443719490 |pmid=14586189 |s2cid=1041409}}</ref> Factors such as unemployment that lead to insufficient resources in the household can increase marital stress and therefore exacerbate domestic violence.<ref name="violence">{{Cite journal |last=Magar |first=Veronica |title=Empowerment approaches to gender-based violence: women's courts in Delhi slums |journal=[[Women's Studies International Forum]] |volume=26 |issue=6 |pages=509–523 |doi=10.1016/j.wsif.2003.09.006 |date=November–December 2003}}</ref>

Slums are often non-secured areas and women often risk [[sexual violence]] when they walk alone in slums late at night. Violence against women and women's [[security]] in slums emerge as recurrent issues.<ref name="Women in slums">{{cite book |title=Women, Slums and Urbanisation:Examining the Causes and Consequences |year=2008 |publisher=Centre on Housing Rights and Evictions (COHRE) |location=Geneva |isbn=978-92-95004-42-9}}</ref>{{page needed|date=October 2024}}

Another prevalent form of violence in slums is armed violence ([[gun violence]]), mostly existing in African and Latin American slums. It leads to [[homicide]] and the emergence of criminal gangs.<ref>{{cite news |last=Palus |first=Nancy |title=Humanitarian intervention in violence-hit slums – from whether to how |url=http://www.irinnews.org/report/98038/humanitarian-intervention-in-violence-hit-slums-from-whether-to-how |access-date=November 1, 2013 |publisher=IRIN |archive-url=https://web.archive.org/web/20131105054241/http://www.irinnews.org/report/98038/humanitarian-intervention-in-violence-hit-slums-from-whether-to-how |archive-date=November 5, 2013 |url-status=live}}</ref> Typical victims are male slum residents.<ref name="armedviolence">[http://www.genevadeclaration.org/fileadmin/docs/regional-publications/Armed-Violence-and-Urbanization-in-Africa.pdf "More Slums Equals More Violence"] {{Webarchive|url=https://web.archive.org/web/20130921055802/http://www.genevadeclaration.org/fileadmin/docs/regional-publications/Armed-Violence-and-Urbanization-in-Africa.pdf |date=2013-09-21}} Robert Muggah and Anna Alvazzi del Frate, Geneva Declaration on Armed Violence and Development & UNDP (October 2007)</ref><ref>{{cite journal |hdl=10520/EJC93065 |first1=Anne |last1=Outwater |first2=Jacquelyn C. |last2=Campbell |first3=Daniel |last3=Webster |first4=Edward |last4=Mgaya |title=Homicide Death in Sub-Saharan Africa: A Review 1970–2004|journal=African Safety Promotion |year=2007 |volume=5 |issue=1 |pages=31–44 |doi=10.4314/asp.v5i1.31632}}</ref> Violence often leads to retaliatory and vigilante violence within the slum.<ref>{{cite journal |doi=10.1007/s12116-013-9134-y |title=Violence and Urban Order in Nairobi, Kenya and Lagos, Nigeria |journal=Studies in Comparative International Development |volume=48 |issue=3 |pages=240–262 |year=2013 |last1=Lebas |first1=Adrienne |s2cid=153350971}}</ref> Gang and drug wars are endemic in some slums, predominantly between male residents of slums.<ref name="gang">{{Cite thesis |type=PhD thesis |oclc=855972637 |hdl=1885/109799 |last=Rashid |first=Sabina Faiz |title=Worried lives, poverty and reproductive health needs of married adolescent women in urban slums of Dhaka city, Bangladesh |publisher=Australian National University |year=2005 |doi=10.25911/5d7784bca626a}}</ref><ref name="violencemen">{{cite journal |last=Ochako |first=Rhoune Adhiambo |title=Gender-Based Violence in the Context of Urban Poverty: Experiences of Men from the Slums of Nairobi, Kenya |journal=Population Association of America 2011 Annual Meeting Program |year=2011 |display-authors=etal |url=http://paa2011.princeton.edu/abstracts/111316}}</ref> The police sometimes participate in gender-based violence against men as well by picking up some men, beating them and putting them in jail. [[Domestic violence against men]] also exists in slums, including verbal abuses and even physical violence from households.<ref name="violencemen" />

Cohen as well as Merton theorized that the cycle of slum violence does not mean slums are inevitably criminogenic, rather in some cases it is frustration against life in slum, and a consequence of denial of opportunity to slum residents to leave the slum.<ref>{{cite journal |doi=10.2307/2084686 |jstor=2084686 |title=Social Structure and Anomie |journal=American Sociological Review |volume=3 |issue=5 |pages=672–682 |last1=Merton |first1=Robert K. |year=1938}}</ref><ref>S Cohen (1971), ''Images of deviance'', Harmondsworth, UK, Penguin</ref>{{page needed|date=October 2024}}<ref>''Criminological Theory: Context and Consequences'', J. Robert Lilly, Francis T. Cullen, Richard A. Ball (2010), 5th Edition, SAGE, {{ISBN|978-1412981453}}, pages 41–69</ref>

[[File:A young boy sits over an open sewer in the Kibera slum, Nairobi.jpg|thumb|A young boy sits over an open sewer in the Kibera slum, [[Nairobi]].]]

===Infectious diseases and epidemics===
Slum dwellers usually experience a high rate of disease.<ref name="Ezeh-History-Slums">{{cite journal |doi=10.1016/S0140-6736(16)31650-6 |pmid=27760703 |title=The history, geography, and sociology of slums and the health problems of people who live in slums |journal=The Lancet |volume=389 |issue=10068 |pages=547–558 |year=2017 |last1=Ezeh |first1=Alex |last2=Oyebode |first2=Oyinlola |last3=Satterthwaite |first3=David |last4=Chen |first4=Yen-Fu |last5=Ndugwa |first5=Robert |last6=Sartori |first6=Jo |last7=Mberu |first7=Blessing |last8=Melendez-Torres |first8=G. J. |last9=Haregu |first9=Tilahun |last10=Watson |first10=Samuel I. |last11=Caiaffa |first11=Waleska |last12=Capon |first12=Anthony |last13=Lilford |first13=Richard J. |s2cid=3514638 |url=http://wrap.warwick.ac.uk/83209/1/WRAP_Slum%20Health%20Paper%201%20-%20RESUBMISSION_FINALCOPY_CLEAN.pdf |access-date=2019-07-10 |archive-url=https://web.archive.org/web/20180719214842/http://wrap.warwick.ac.uk/83209/1/WRAP_Slum%20Health%20Paper%201%20-%20RESUBMISSION_FINALCOPY_CLEAN.pdf |archive-date=2018-07-19 |url-status=live}}</ref><ref name="pmid27760702" /> Diseases that have been reported in slums include [[cholera]],<ref>{{Cite news |last=Nossiter |first=Adam |title=Cholera Epidemic Envelops Coastal Slums in West Africa |url=https://www.nytimes.com/2012/08/23/world/africa/cholera-epidemic-envelops-coastal-slums-in-west-africa.html?_r=1& |access-date=November 20, 2013 |newspaper=The New York Times |date=2012-08-22 |archive-url=https://web.archive.org/web/20150108233013/http://www.nytimes.com/2012/08/23/world/africa/cholera-epidemic-envelops-coastal-slums-in-west-africa.html?_r=1& |archive-date=January 8, 2015 |url-status=live}}</ref><ref>[http://www.africa-health.com/articles/september_2012/Newsdesk.pdf "Cholera epidemic envelops coastal slums in West Africa, Africa Health"]{{Dead link|date=July 2018 |bot=InternetArchiveBot |fix-attempted=yes}}, page 10 (September 2012)</ref> [[HIV/AIDS]],<ref>{{cite journal |doi=10.1016/j.healthplace.2012.04.003 |pmid=22591621 |pmc=3427858 |title=Are slum dwellers at heightened risk of HIV infection than other urban residents? Evidence from population-based HIV prevalence surveys in Kenya |journal=Health & Place |volume=18 |issue=5 |pages=1144–1152 |year=2012 |last1=Madise |first1=Nyovani J.|author1-link=Nyovani Madise|last2=Ziraba |first2=Abdhalah K. |last3=Inungu |first3=Joseph |last4=Khamadi |first4=Samoel A. |last5=Ezeh |first5=Alex |last6=Zulu |first6=Eliya M. |last7=Kebaso |first7=John |last8=Okoth |first8=Vincent |last9=Mwau |first9=Matilu}}</ref><ref>{{cite journal |doi=10.1016/j.healthplace.2012.04.013 |pmid=22704913 |pmc=3483073 |title=The built environment & the impact of neighborhood characteristics on youth sexual risk behavior in Cape Town, South Africa |journal=Health & Place |volume=18 |issue=5 |pages=1088–1100 |year=2012 |last1=Burns |first1=Paul A. |last2=Snow |first2=Rachel C.}}</ref> [[measles]],<ref>[https://web.archive.org/web/20190913154349/http://medind.nic.in/ibl/t08/i3/iblt08i3p168.pdf "Measles Outbreak – a Study in Migrant Population in Aligarh"] Najam Khalique et al, ''Indian Journal of Preventive & Social Medicine'' Vol. 39 No. 3&4 2008</ref> [[malaria]],<ref>{{cite journal |doi=10.1186/1475-2875-12-176 |pmid=23721247 |pmc=3691654 |title=Vivax malaria and bacteraemia: A prospective study in Kolkata, India |journal=Malaria Journal |volume=12 |article-number=176 |year=2013 |last1=Bhattacharya |first1=Sujit |last2=Sur |first2=Dipika |last3=Dutta |first3=Shanta |last4=Kanungo |first4=Suman |last5=Ochiai |first5=R Leon |last6=Kim |first6=Deok |last7=Anstey |first7=Nicholas M. |last8=von Seidlein |first8=Lorenz |last9=Deen |first9=Jacqueline |doi-access=free}}</ref> [[dengue]],<ref>{{cite journal |doi=10.1093/trstmh/trs011 |pmid=23222946 |title=Geographical distribution and spatio-temporal patterns of dengue cases in Jeddah Governorate from 2006-2008 |journal=Transactions of the Royal Society of Tropical Medicine and Hygiene |volume=107 |issue=1 |pages=23–29 |year=2012 |last1=Alzahrani |first1=A. G. |last2=Al Mazroa |first2=M. A. |last3=Alrabeah |first3=A. M. |last4=Ibrahim |first4=A. M. |last5=Mokdad |first5=A. H. |last6=Memish |first6=Z. A.}}</ref> [[typhoid]],<ref>{{cite journal |doi=10.1186/1476-072X-12-13 |pmid=23497202 |pmc=3610306 |title=Modelling typhoid risk in Dhaka Metropolitan Area of Bangladesh: The role of socio-economic and environmental factors |journal=International Journal of Health Geographics |volume=12 |page=13 |year=2013 |last1=Corner |first1=Robert J. |last2=Dewan |first2=Ashraf M. |last3=Hashizume |first3=Masahiro |doi-access=free}}</ref> drug resistant [[tuberculosis]],<ref>{{cite journal |doi=10.1186/1471-2458-12-536 |pmid=22824498 |pmc=3507884 |title=Socio-demographic determinants and prevalence of Tuberculosis knowledge in three slum populations of Uganda |journal=BMC Public Health |volume=12 |article-number=536 |year=2012 |last1=Obuku |first1=Ekwaro A. |last2=Meynell |first2=Clea |last3=Kiboss-Kyeyune |first3=Jemimah |last4=Blankley |first4=Simon |last5=Atuhairwe |first5=Christine |last6=Nabankema |first6=Evelyn |last7=Lab |first7=Morris |last8=Jeffrey |first8=Nikki |last9=Ndungutse |first9=David |doi-access=free}}</ref><ref>[http://www.worldbank.org/en/news/feature/2013/05/09/india-battling-tb-in-indias-slums "India: Battling TB in India's slums"]. The World Bank. May 9, 2013.</ref> and other [[epidemics]].<ref>{{cite journal |doi=10.1186/1471-2334-9-147 |pmid=19732423 |pmc=2749047 |title=Leptospirosis in the Asia Pacific region |journal=BMC Infectious Diseases |volume=9 |article-number=147 |year=2009 |last1=Victoriano |first1=Ann Florence B. |last2=Smythe |first2=Lee D. |last3=Gloriani-Barzaga |first3=Nina |last4=Cavinta |first4=Lolita L. |last5=Kasai |first5=Takeshi |last6=Limpakarnjanarat |first6=Khanchit |last7=Ong |first7=Bee Lee |last8=Gongal |first8=Gyanendra |last9=Hall |first9=Julie |last10=Coulombe |first10=Caroline Anne |last11=Yanagihara |first11=Yasutake |last12=Yoshida |first12=Shin-Ichi |last13=Adler |first13=Ben |doi-access=free}}</ref><ref>{{cite journal |doi=10.1371/journal.pntd.0000877 |pmid=21072238 |pmc=2970542 |title=Risk Factors for Death in Children with Visceral Leishmaniasis |journal=PLOS Neglected Tropical Diseases |volume=4 |issue=11 |article-number=e877 |year=2010 |last1=Sampaio |first1=Márcia Jaqueline Alves de Queiroz |last2=Cavalcanti |first2=Nara Vasconcelos |last3=Alves |first3=João Guilherme Bezerra |last4=Fernandes Filho |first4=Mário Jorge Costa |last5=Correia |first5=Jailson B. |doi-access=free}}</ref> Studies focus on children's health in slums address that [[cholera]] and [[diarrhea]] are especially common among young children.<ref name="cholera">{{cite journal |doi=10.1136/adc.2004.071316 |pmid=15964861 |pmc=1720149 |title=The burden of cholera in the slums of Kolkata, India: Data from a prospective, community based study |journal=Archives of Disease in Childhood |volume=90 |issue=11 |pages=1175–1181 |year=2005 |last1=Sur |first1=D. |last2=Deen |first2=J. L. |last3=Manna |first3=B. |last4=Niyogi |first4=S. K. |last5=Deb |first5=A. K. |last6=Kanungo |first6=S. |last7=Sarkar |first7=B. L. |last8=Kim |first8=D. R. |last9=Danovaro-Holliday |first9=M. C. |last10=Holliday |first10=K. |last11=Gupta |first11=V. K. |last12=Ali |first12=M. |last13=von Seidlein |first13=L. |last14=Clemens |first14=J. D. |last15=Bhattacharya |first15=S. K.}}</ref><ref>{{cite journal |doi=10.1371/journal.pntd.0000173 |pmid=18299707 |pmc=2254203 |title=The High Burden of Cholera in Children: Comparison of Incidence from Endemic Areas in Asia and Africa |journal=PLOS Neglected Tropical Diseases |volume=2 |issue=2 |article-number=e173 |year=2008 |last1=Deen |first1=Jacqueline L. |last2=von Seidlein |first2=Lorenz |last3=Sur |first3=Dipika |last4=Agtini |first4=Magdarina |last5=Lucas |first5=Marcelino E. S. |last6=Lopez |first6=Anna Lena |last7=Kim |first7=Deok Ryun |last8=Ali |first8=Mohammad |last9=Clemens |first9=John D. |doi-access=free}}</ref> Besides children's vulnerability to diseases, many scholars also focus on high HIV/AIDS prevalence in slums among women.<ref>{{cite journal |doi=10.1016/j.socscimed.2008.11.023 |pmid=19070950 |title=Vulnerability to HIV/AIDS among women of reproductive age in the slums of Delhi and Hyderabad, India |journal=Social Science & Medicine |volume=68 |issue=4 |pages=638–642 |year=2009 |last1=Ghosh |first1=Jayati |last2=Wadhwa |first2=Vandana |last3=Kalipeni |first3=Ezekiel}}</ref><ref>{{cite journal |doi=10.1007/s10461-008-9485-y |pmid=18998204 |title=Effects of Micro-Enterprise Services on HIV Risk Behaviour Among Female Sex Workers in Kenya's Urban Slums |journal=AIDS and Behavior |volume=13 |issue=3 |pages=449–461 |year=2008 |last1=Odek |first1=Willis Omondi |last2=Busza |first2=Joanna |last3=Morris |first3=Chester N. |last4=Cleland |first4=John |last5=Ngugi |first5=Elizabeth N. |last6=Ferguson |first6=Alan G. |s2cid=5608709}}</ref> Throughout slum areas in various parts of the world, infectious diseases are a significant contributor to high mortality rates.<ref>{{Cite journal|last=Eisenstein|first=Michael|date=2016-03-16|title=Disease: Poverty and pathogens|journal=Nature|volume=531|issue=7594|pages=S61–S63|doi=10.1038/531S61a|pmid=26981732|issn=0028-0836|bibcode=2016Natur.531S..61E|doi-access=free}}</ref> For example, according to a study in Nairobi's slums, HIV/AIDS and tuberculosis attributed to about 50% of the mortality burden.<ref>{{cite journal |doi=10.1186/1478-7954-6-1 |pmid=18331630 |pmc=2292687 |title=The burden of disease profile of residents of Nairobi's slums: Results from a Demographic Surveillance System |journal=Population Health Metrics |volume=6 |article-number=1 |year=2008 |last1=Kyobutungi |first1=Catherine |last2=Ziraba |first2=Abdhalah Kasiira |last3=Ezeh |first3=Alex |last4=Yé |first4=Yazoumé |doi-access=free}} Slums can also cause the disease of blackening of the body which is known as "Black Bund"</ref>

Factors that have been attributed to a higher rate of disease transmission in slums include high [[population densities]], poor living conditions, low [[vaccination]] rates, insufficient health-related data and inadequate [[health service]].<ref>{{Cite journal |last1=Ezeh |first1=Alex |last2=Oyebode |first2=Oyinlola |last3=Satterthwaite |first3=David |last4=Chen |first4=Yen-Fu |last5=Ndugwa |first5=Robert |last6=Sartori |first6=Jo |last7=Mberu |first7=Blessing |last8=Melendez-Torres |first8=G J |last9=Haregu |first9=Tilahun |date=February 2017 |title=The history, geography, and sociology of slums and the health problems of people who live in slums |journal=The Lancet |volume=389 |issue=10068 |pages=547–558 |doi=10.1016/S0140-6736(16)31650-6 |pmid=27760703 |s2cid=3514638 |url=http://wrap.warwick.ac.uk/83209/1/WRAP_Slum%20Health%20Paper%201%20-%20RESUBMISSION_FINALCOPY_CLEAN.pdf |access-date=2019-07-10 |archive-url=https://web.archive.org/web/20180719214842/http://wrap.warwick.ac.uk/83209/1/WRAP_Slum%20Health%20Paper%201%20-%20RESUBMISSION_FINALCOPY_CLEAN.pdf |archive-date=2018-07-19 |url-status=live}}</ref> Overcrowding leads to faster and wider spread of diseases due to the limited space in slum housing.<ref name="Ezeh-History-Slums" /><ref name="pmid27760702" /> Poor living conditions also make slum dwellers more vulnerable to certain diseases. Poor [[water quality]], a manifest example, is a cause of many major illnesses including [[malaria]], [[diarrhea]] and [[trachoma]].<ref>{{cite book |last=World Health Organization |title=Water, Sanitation and Hygiene Links to Health: Facts and Figures |year=2004}}</ref>{{page needed|date=October 2018}} Improving living conditions such as introduction of better sanitation and access to basic facilities can ameliorate the effects of diseases, such as cholera.<ref name="cholera" /><ref>{{Cite journal |last=Sur |first=D |date=2005-11-01 |title=The burden of cholera in the slums of Kolkata, India: data from a prospective, community based study |journal=Archives of Disease in Childhood |volume=90 |issue=11 |pages=1175–1181 |doi=10.1136/adc.2004.071316 |pmid=15964861 |pmc=1720149 |issn=0003-9888}}</ref>

Slums have been historically linked to epidemics, and this trend has continued in modern times.<ref>Reiter, P., & Goh, K. T. (1998), "Dengue control in Singapore", ''Dengue in Singapore'', pp. 213-242, {{ISBN|981-04-0164-7}}</ref><ref>{{cite journal |last1=Swaminathan |first1=Madhura |year=2016 |title=Aspects of urban poverty in Bombay |journal=Environment and Urbanization |volume=7 |pages=133–144 |doi=10.1177/095624789500700117 |s2cid=55748580}}</ref><ref>{{cite journal |last1=Sclar |first1=Elliott D. |last2=Garau |first2=Pietro |last3=Carolini |first3=Gabriella |year=2005 |title=The 21st century health challenge of slums and cities |journal=The Lancet |volume=365 |issue=9462 |pages=901–903 |doi=10.1016/S0140-6736(05)71049-7 |pmid=15752535 |s2cid=17297343}}</ref> For example, the slums of West African nations such as [[Liberia]] were crippled by as well as contributed to the outbreak and spread of [[Ebola]] in 2014.<ref>[https://www.washingtonpost.com/world/africa/in-a-liberian-slum-swarming-with-ebola-a-race-against-time-to-save-two-little-girls/2014/10/27/7f14e5ac-1b77-4d48-adef-de19e07e7651_story.html "In a Liberian slum swarming with Ebola, a race against time to save two little girls"] {{Webarchive|url=https://web.archive.org/web/20180201103310/https://www.washingtonpost.com/world/africa/in-a-liberian-slum-swarming-with-ebola-a-race-against-time-to-save-two-little-girls/2014/10/27/7f14e5ac-1b77-4d48-adef-de19e07e7651_story.html |date=2018-02-01}} ''The Washington Post''</ref><ref>[https://online.wsj.com/articles/liberian-slum-takes-ebola-treatment-into-its-own-hands-1414080932 "Liberian Slum Takes Ebola Treatment Into Its Own Hands"] {{Webarchive|url=https://web.archive.org/web/20141101020713/http://online.wsj.com/articles/liberian-slum-takes-ebola-treatment-into-its-own-hands-1414080932 |date=2014-11-01}} ''The Wall Street Journal''</ref> Slums are considered a major [[public health]] concern and potential breeding grounds of drug resistant diseases for the entire city, the nation, as well as the global community.<ref>Thomas Quinn and John Bartlett, (2010), "Global infectious diseases and urbanization", ''Urban Health: Global Perspectives'', 18, 105; {{ISBN|978-0-470-42206-9}}</ref><ref>{{cite journal |last1=Alirol |first1=Emilie |last2=Getaz |first2=Laurent |last3=Stoll |first3=Beat |last4=Chappuis |first4=François |last5=Loutan |first5=Louis |year=2011 |title=Urbanisation and infectious diseases in a globalised world |journal=The Lancet Infectious Diseases |volume=11 |issue=2 |pages=131–141 |doi=10.1016/S1473-3099(10)70223-1 |pmid=21272793 |pmc=7106397}}</ref>

===Child malnutrition===
Child [[malnutrition]] is more common in slums than in non-slum areas.<ref name="malnutritionchildren">{{cite journal |pmid=15297683 |url=http://www.indianpediatrics.net/july2004/july-682-696.htm |title=Indian Pediatrics - Editorial |journal=Indian Pediatrics |volume=41 |issue=7 |pages=682–96 |year=2004 |last1=Ghosh |first1=S. |last2=Shah |first2=D. |access-date=2018-10-11 |archive-url=https://web.archive.org/web/20180322001735/http://www.indianpediatrics.net/july2004/july-682-696.htm |archive-date=2018-03-22 |url-status=live}}</ref> In [[Mumbai]] and [[New Delhi]], 47% and 51% of slum children under the age of five are stunted and 35% and 36% of them are underweight. These children all suffer from third-degree malnutrition, the most severe level, according to [[WHO]] standards.<ref>{{cite report |publisher=Dasra and Piramal |title=Nourishing our Future: Tackling Child Malnutrition in Urban Slums |date=March 2011 |url=https://www.dasra.org/individual-resources/35 |page=8 |access-date=October 20, 2024}}</ref> A study conducted by Tada et al. in [[Bangkok]] slums illustrates that in terms of weight-forage, 25.4% of the children who participated in the survey suffered from malnutrition, compared to around 8% national malnutrition prevalence in [[Thailand]].<ref name="bangkok">{{cite journal |pmid=12693602 |year=2002 |last1=Tada |first1=Y. |title=Nutritional status of the preschool children of the Klong Toey slum, Bangkok |journal=The Southeast Asian Journal of Tropical Medicine and Public Health |volume=33 |issue=3 |pages=628–37 |last2=Keiwkarnka |first2=B. |last3=Pancharuniti |first3=N. |last4=Chamroonsawasdi |first4=K.}}</ref> In [[Ethiopia]] and the [[Niger]], rates of child malnutrition in urban slums are around 40%.<ref>{{cite book |last=United Nations Human Settlements Programme |title=State of the world's cities 2006/7 |year=2006 |publisher=Earthscan Publications |location=London}}</ref>{{page needed|date=October 2018}}

The major nutritional problems in slums are [[protein-energy malnutrition]] (PEM), [[vitamin A deficiency]] (VAD), [[iron deficiency anemia]] (IDA) and [[iodine deficiency disorders]] (IDD).<ref name="malnutritionchildren" /> Malnutrition can sometimes lead to [[death]] among children.<ref>{{cite news |last=Karim |first=Md Rezaul |title=Children suffering malnutrition in a slum |newspaper=Wikinut-guides-activism |date=January 11, 2012}}</ref> Dr. [[Abhay Bang]]'s report shows that malnutrition kills 56,000 children annually in urban slums in India.<ref>{{cite news|last=Punwani |first=Jyoti |title=Malnutrition kills 56,000 children annually in urban slums |url=https://timesofindia.indiatimes.com/home/opinion/interviews/Malnutrition-kills-56000-children-annually-in-urban-slums/articleshow/7248634.cms |date=January 10, 2011 |access-date=November 5, 2013 |archive-url=https://web.archive.org/web/20131105064845/http://articles.timesofindia.indiatimes.com/2011-01-10/interviews/28373285_1_malnutrition-integrated-child-development-scheme-healthcare-system |archive-date=November 5, 2013 |newspaper=[[The Times of India]] |url-status=live}}</ref>

Widespread child malnutrition in slums is closely related to family [[income]], mothers' food practice, mothers' [[educational]] level, and maternal employment or housewifery.<ref name="bangkok" /> [[Poverty]] may result in inadequate [[food]] intake when people cannot afford to buy and store enough food, which leads to malnutrition.<ref name="nutrition">{{cite journal |last=Gomber |first=Sunil |title=Prevalence & etiology of nutritional anaemia among school children of urban slums |journal=Indian Journal of Medical Research |year=2003 |volume=118 |pages=167–171 |display-authors=etal |pmid=14700351}}</ref> Another common cause is mothers' faulty feeding practices, including inadequate [[breastfeeding]] and wrongly preparation of food for children.<ref name="malnutritionchildren" /> Tada et al.'s study in Bangkok slums shows that around 64% of the mothers sometimes fed their children [[instant food]] instead of a normal meal. And about 70% of the mothers did not provide their children three meals every day. Mothers' lack of education leads to their faulty feeding practices. Many mothers in slums don't have knowledge on food nutrition for children.<ref name="bangkok" /> Maternal employment also influences children's nutritional status. For the mothers who work outside, their children are prone to be malnourished. These children are likely to be neglected by their mothers or sometimes not carefully looked after by their female relatives.<ref name="malnutritionchildren" />

=== Other non-communicable diseases ===
A multitude of non-contagious diseases also impact health for slum residents. Examples of prevalent non-infectious diseases include: cardiovascular disease, diabetes, chronic respiratory disease, neurological disorders, and mental illness.<ref>{{Cite journal |last1=Snyder |first1=Robert |last2=Rajan |first2=Jayant |last3=Costa |first3=Federico |last4=Lima |first4=Helena |last5=Calcagno |first5=Juan |last6=Couto |first6=Ricardo |last7=Riley |first7=Lee |last8=Reis |first8=Mitermayer |last9=Ko |first9=Albert |date=2017-09-16 |title=Differences in the Prevalence of Non-Communicable Disease between Slum Dwellers and the General Population in a Large Urban Area in Brazil |journal=Tropical Medicine and Infectious Disease |volume=2 |issue=3 |page=47 |doi=10.3390/tropicalmed2030047 |issn=2414-6366 |pmc=6082112 |pmid=30270904 |doi-access=free}}</ref> In some slum areas of India, diarrhea is a significant health problem among children. Factors like poor sanitation, low literacy rates, and limited awareness make diarrhea and other dangerous diseases extremely prevalent and burdensome on the community.<ref>{{Cite journal |last1=Pahwa |first1=Smriti |last2=Kumar |first2=Geeta Trilok |last3=Toteja |first3=G. S. |date=December 2010 |title=Performance of a community-based health and nutrition-education intervention in the management of diarrhoea in a slum of Delhi, India |journal=Journal of Health, Population, and Nutrition |volume=28 |issue=6 |pages=553–559 |issn=1606-0997 |pmc=2995023 |pmid=21261200 |doi=10.3329/jhpn.v28i6.6603 |bibcode=2010JHPN...28.6603P }}</ref>

Lack of reliable data also has a negative impact on slum dwellers' health. A number of slum families do not report cases or seek professional medical care, which results in insufficient data.<ref name="measles">{{cite journal |last=Desai |first=V.K. |author2=el al. |year=2003 |title=Study of measles incidence and vaccination coverage in slums of Surat city |journal=Indian Journal of Community Medicine |volume=28 |issue=1}}</ref> This might prevent appropriate allocation of health care resources in slum areas since many countries base their health care plans on data from clinic, hospital, or national mortality registry.<ref name="disease">{{cite journal |last1=Riley |first1=Lee W. |last2=Ko |first2=Albert I. |last3=Unger |first3=Alon |last4=Reis |first4=Mitermayer G. |year=2007 |title=Slum health: Diseases of neglected populations |journal=BMC International Health and Human Rights |volume=7 |article-number=2 |doi=10.1186/1472-698x-7-2 |pmc=1829399 |pmid=17343758 |doi-access=free}}</ref> Moreover, [[health service]] is insufficient or inadequate in most of the world's slums.<ref name="disease" /> Emergency [[ambulance]] service and [[urgent care]] services are typically unavailable, as health service providers sometimes avoid servicing slums.<ref>{{cite journal |last1=Marsh |first1=D. R. |last2=Kadir |first2=M. M. |last3=Husein |first3=K. |last4=Luby |first4=S. P. |last5=Siddiqui |first5=R. |last6=Khalid |first6=S. B. |year=2000 |title=Adult Mortality in Slums of Karachi, Pakistan |url=http://jpma.org.pk/full_article_text.php?article_id=3087 |journal=The Journal of the Pakistan Medical Association |volume=50 |issue=9 |pages=300–6 |pmid=11043020 |access-date=2018-10-11 |archive-url=https://web.archive.org/web/20181012054027/http://jpma.org.pk/full_article_text.php?article_id=3087 |archive-date=2018-10-12 |url-status=live}}</ref><ref name="disease" /> A study shows that more than half of slum dwellers are prone to visit private practitioners or seek [[self-medication]] with medicines available in the home.<ref>{{cite journal |last1=Zaidi |first1=S. S. |last2=Seidlein |first2=L. V. |last3=Nizami |first3=S. Q. |last4=Acosta |first4=C. |last5=Bhutta |first5=Z. A. |year=2006 |title=Health care utilization for diarrhea and fever in 4 urban slums in Karachi |journal=Journal of the College of Physicians and Surgeons--Pakistan |volume=16 |issue=4 |pages=245–8 |pmid=16624184}}</ref> Private practitioners in slums are usually those who are unlicensed or poorly trained and they run clinics and pharmacies mainly for the sake of money.<ref name="disease" /> The categorization of slum health by the government and census data also has an effect on the distribution and allocation of health resources in inner city areas. A significant portion of city populations face challenges with access to health care but do not live in locations that are described as within the "slum" area.<ref>{{Cite journal |last1=Ezeh |first1=Alex |last2=Oyebode |first2=Oyinlola |last3=Satterthwaite |first3=David |last4=Chen |first4=Yen-Fu |last5=Ndugwa |first5=Robert |last6=Sartori |first6=Jo |last7=Mberu |first7=Blessing |last8=Melendez-Torres |first8=G J |last9=Haregu |first9=Tilahun |date=February 2017 |title=The history, geography, and sociology of slums and the health problems of people who live in slums |journal=The Lancet |volume=389 |issue=10068 |pages=547–558 |doi=10.1016/s0140-6736(16)31650-6 |pmid=27760703 |s2cid=3514638 |issn=0140-6736 |url=http://wrap.warwick.ac.uk/83209/1/WRAP_Slum%20Health%20Paper%201%20-%20RESUBMISSION_FINALCOPY_CLEAN.pdf |access-date=2019-07-10 |archive-url=https://web.archive.org/web/20180719214842/http://wrap.warwick.ac.uk/83209/1/WRAP_Slum%20Health%20Paper%201%20-%20RESUBMISSION_FINALCOPY_CLEAN.pdf |archive-date=2018-07-19 |url-status=live}}</ref>

Overall, a complex network of physical, social, and environmental factors contribute to the health threats faced by slum residents.<ref>{{Cite journal |last=The Lancet |date=February 2017 |title=Health in slums: understanding the unseen |journal=The Lancet |volume=389 |issue=10068 |page=478 |doi=10.1016/S0140-6736(17)30266-0 |pmid=28170319 |doi-access=free}}</ref>

==Countermeasures==
[[File:Villa_31_de_Buenos_Aires.jpeg|thumb|Villa 31, one of the largest slums of [[Argentina]], located near the center of [[Buenos Aires]]]]
Recent years have seen a dramatic growth in the number of slums as urban populations have increased in [[developing countries]].<ref>Adam Parsons (2010), [http://www.stwr.org/downloads/pdfs/7_myths_report.pdf "The Seven Myths of Slums: Challenging popular prejudices about the world's urban poor"] {{Webarchive|url=https://web.archive.org/web/20120510222656/http://www.stwr.org/downloads/pdfs/7_myths_report.pdf |date=2012-05-10}}, {{ISBN|978-1-907121-02-9}}; page 14</ref> Nearly a billion people worldwide live in slums, and some project the figure may grow to 2 billion by 2030 if governments and the global community ignore slums and continue current urban policies. United Nations Habitat group believes change is possible.<ref name="unh2007a">[http://www.unhabitat.org/downloads/docs/4631_46759_GC%2021%20Slum%20dwellers%20to%20double.pdf Slum Dwellers to double by 2030] {{webarchive|url=https://web.archive.org/web/20130317043415/http://www.unhabitat.org/downloads/docs/4631_46759_GC%2021%20Slum%20dwellers%20to%20double.pdf |date=2013-03-17}} UN-Habitat report, April 2007.</ref>

Some NGO's are focused at addressing local problems (i.e. sanitation issues, health, ...), through the [[map]]ping out of the slums and its health services,<ref>[https://wiki.openstreetmap.org/wiki/Slummapping "Slummapping"].</ref> creation of [[latrine]]s,<ref>{{cite journal |jstor=27752043 |title=The Role of Government and NGOs in Slum Development: The Case of Dhaka City |last1=Habib |first1=Enamul |journal=Development in Practice |date=2009 |volume=19 |issue=2 |pages=259–265 |doi=10.1080/09614520802689576 |s2cid=132760561}}</ref> creation of [[Urban agriculture|local food production]] projects, and even [[microcredit]] projects.<ref>{{Cite web|url=https://www.liveinslums.org/en/about|title=LiveinSlums|website=www.liveinslums.org}}</ref> In one project (in Rio de Janeiro), the government even [[Employment|employed]] slum residents for the [[reforestation]] of a nearby location.<ref>{{Cite web|url=https://www.worldbank.org/en/news/feature/2013/11/11/Reforestation-slums-Rio-de-Janeiro-Brazil-biodiversity-climate-change|title=Reforestation in Rio: More birds, less greenhouse gases, safer favelas|website=World Bank}}</ref><ref>{{Cite web|url=https://www.newsecuritybeat.org/2009/01/in-rio-de-janeiro-an-opportunity-to-break-barriers/|title=In Rio de Janeiro, an Opportunity to Break Barriers|date=January 23, 2009}}</ref>

To achieve the goal of "cities without slums", the UN claims that governments must undertake vigorous urban planning, city management, infrastructure development, slum upgrading and poverty reduction.<ref name="unh2007a" /> 

===Slum removal===
{{main|Slum clearance}}
[[File:Slum in Borgergade-Aderlsgade.jpg|thumb|A slum dwelling in [[Borgergade]] in central Copenhagen, [[Denmark]], about 1940. The Danish government passed The Slum Clearance Act in 1939, demolished many slums including Borgergade, replacing it with modern buildings by the early 1950s.<ref name="kbt2012">Kristian Buhl Thomsen (2012), [http://www.byhistorie.dk/filer/Modernism-and-Urban-Renewal-in-Denmark-1939-1983.pdf "Modernism and Urban Renewal in Denmark 1939–1983"] {{Webarchive|url=https://web.archive.org/web/20130921061603/http://www.byhistorie.dk/filer/Modernism-and-Urban-Renewal-in-Denmark-1939-1983.pdf |date=2013-09-21}}, Aarhus University, 11th Conference on Urban History, EAUH, Prague</ref><ref>See (in Danish): "Lov om Boligtilsyn og Sanering af usunde Bydele", ''[[Rigsdagstidende]]'', 1939, pages 1250–1260</ref>]]
Some city and state officials have simply sought to remove slums.<ref>[http://dawn.com/news/1038145/slum-dwellers-refuse-to-vacate-railway-land "Slum dwellers refuse to vacate railway land"] {{Webarchive|url=https://web.archive.org/web/20130921055553/http://dawn.com/news/1038145/slum-dwellers-refuse-to-vacate-railway-land |date=2013-09-21}}, ''[[Dawn (newspaper)|Dawn]]'', Rawalpindi, Pakistan (August 24, 2013)</ref><ref>[http://www.hindustantimes.com/India-news/Gurgaon/Homeless-labourers-protest-razing-of-slums/Article1-1047924.aspx "Homeless labourers protest razing of slums"] {{Webarchive|url=https://web.archive.org/web/20130921061534/http://www.hindustantimes.com/India-news/Gurgaon/Homeless-labourers-protest-razing-of-slums/Article1-1047924.aspx |date=2013-09-21}} ''The Hindustan Times'', Gurgaon, India (April 21, 2013)</ref> This strategy for dealing with slums is rooted in the fact that slums typically start illegally on someone else's land property, and they are not recognized by the state. As the slum started by violating another's property rights, the residents have no legal claim to the land.<ref>Gardiner, B. (1997), "Squatters' Rights and Adverse Possession: A Search for Equitable Application of Property Laws". ''Indiana International & Comparative Law Review'', 8, 119.</ref><ref>Kross, E. (1992). ''Spontaneous settlements in Lima: urbanization processes in a Latin American metropolis'', Ferdinand Schoningh. {{ISBN|3-506-71265-9}}.</ref>{{Page needed|date=October 2024}}

Critics argue that slum removal by force tend to ignore the social problems that cause slums. The poor children as well as working adults of a city's informal economy need a place to live. Slum clearance removes the slum, but it does not remove the causes that create and maintain the slum.<ref>{{cite journal |doi=10.1093/wbro/1.2.183 |title=Shelter Strategies for the Urban Poor in Developing Countries |journal=The World Bank Research Observer |volume=1 |issue=2 |pages=183–203 |year=1986 |last1=Mayo |first1=Stephen K. |last2=Malpezzi |first2=Stephen |last3=Gross |first3=David J. |citeseerx=10.1.1.970.3807}}</ref><ref>{{cite journal |first1=William |last1=Mangin |title=Latin American Squatter Settlements: A Problem and a Solution |journal=Latin American Research Review |volume=2 |issue=3 |year=1967 |pages=65–98 |doi=10.1017/S002387910001534X |jstor=2502178 |s2cid=142274849 |doi-access=free}}</ref> Policymakers, urban planners, and politicians need to take the factors that cause people to live in informal housing into consideration while tackling the issue of slums.<ref name="Strava">{{Cite book |last1=Strava |first1=Cristiana |url=https://rowman.com/ISBN/9781793610652/The-Everyday-Life-of-Urban-Inequality-Ethnographic-Case-Studies-of-Global-Cities |title=The Everyday Life of Urban Inequality: Ethnographic Case Studies of Global Cities |last2=Beier |first2=Raffael |publisher=Lexington Books |location=New York |language=en-us}}</ref>{{page needed|date=October 2024}}

===Slum relocation===
Slum relocation strategies rely on removing the slums and relocating the slum poor to free semi-rural peripheries of cities, sometimes in free housing. An example of this is the governmental program in Morocco called ''Cities without Shantytowns'' (sometimes referred to as ''Cities without Slums'' or, in French, ''Villes Sans Bidonvilles''), which was launched to put an end to informal housing and resettle the communities in slums into apartments.<ref name="Strava" />{{page needed|date=October 2024}}

This strategy ignores several dimensions of a slum life. The strategy sees slum as merely a place where the poor lives. In reality, slums are often integrated with every aspect of a slum resident's life, including sources of employment, distance from work, and social life.<ref>{{cite journal |doi=10.1007/s12132-011-9137-6 |title=Resettlement of Slum Dwellers, Land Tenure Security and Improved Housing, Living and Environmental Conditions at Madina Estate, Accra, Ghana |journal=Urban Forum |volume=23 |issue=3 |pages=343–365 |year=2011 |last1=Nyametso |first1=Johnie Kodjo |s2cid=153513755}}</ref> Slum relocation that displaces the poor from opportunities to earn a livelihood, generates economic insecurity in the poor.<ref>[http://web.mit.edu/urbanupgrading/upgrading/whatis/history.html "Upgrading Urban Communities"] {{Webarchive|url=https://web.archive.org/web/20121110084239/http://web.mit.edu/urbanupgrading/upgrading/whatis/history.html |date=2012-11-10}}, The World Bank, MIT (2009)</ref> In some cases, the slum residents oppose relocation even if the replacement land and housing to the outskirts of cities is of better quality than their current house. Examples include Zone One Tondo Organization of [[Manila]], Philippines, and [[Abahlali baseMjondolo|Abahlali base Mjondolo]] of [[Durban]], South Africa.<ref>Ton Van Naerssen, "Squatter Access to Land in Metro Manila", ''Philippine Studies'' vol. 41, no. 1 (1993) pages 3–20.</ref> In other cases, such as Ennakhil slum relocation project in [[Morocco]], systematic social mediation has worked. The slum residents have been convinced that their current location is a health hazard, prone to natural disaster, or that the alternative location is well connected to employment opportunities.<ref>{{cite journal |doi=10.1016/j.cities.2012.02.005 |title=Between "Authoritarian" and "Empowered" slum relocation: Social mediation in the case of Ennakhil, Morocco |journal=Cities |volume=30 |pages=140–148 |year=2013 |last1=Arandel |first1=Christian |last2=Wetterberg |first2=Anna}}</ref>

===Slum upgrading===
{{Main|Slum upgrading}}

Some governments have begun to approach slums as a possible opportunity to urban development by slum upgrading. This approach was inspired in part by the theoretical writings of [[John F. C. Turner|John Turner]] in 1972.<ref>Turner, J. F. C. and Fichter, R., eds. (1972) ''Freedom to Build''. New York: Macmillan</ref>{{page needed|date=October 2018}}<ref>{{cite journal |doi=10.1016/0197-3975(96)00017-3 |title=Tools for building community |journal=Habitat International |volume=20 |issue=3 |pages=339–347 |year=1996 |last1=Turner |first1=John F.C.}}</ref> The approach seeks to upgrade the slum with basic infrastructure such as [[sanitation]], safe drinking water, safe electricity distribution, paved roads, rain water drainage system, and bus/metro stops.<ref>[http://web.mit.edu/urbanupgrading/upgrading/whatis/what-is.html "What is Urban Upgrading"] {{Webarchive|url=https://web.archive.org/web/20130528035826/http://web.mit.edu/urbanupgrading/upgrading/whatis/what-is.html |date=2013-05-28}} The World Bank Group, MIT (2009)</ref> The assumption behind this approach is that if slums are given basic services and tenure security – that is, the slum will not be destroyed and slum residents will not be evicted, then the residents will rebuild their own housing, engage their slum community to live better, and over time attract investment from government organizations and businesses. Turner argued not to demolish the housing, but to improve the environment: if governments can clear existing slums of unsanitary human waste, polluted water and litter, and from muddy unlit lanes, they do not have to worry about the shanty housing.<ref name="werlin">{{cite journal |doi=10.1080/0042098992908 |title=The Slum Upgrading Myth |journal=Urban Studies |volume=36 |issue=9 |pages=1523–1534 |year=2016 |last1=Werlin |first1=Herbert |s2cid=155052834}}</ref> "[[Squatting|Squatters]]" have shown great organizational skills in terms of land management, and they will maintain the infrastructure that is provided.<ref name="werlin" />

In [[Mexico City]] for example, the government attempted to upgrade and urbanize settled slums in the periphery during the 1970s and 1980s by including basic amenities such as concrete roads, parks, illumination and sewage. Currently, most slums in Mexico City face basic characteristics of traditional slums, characterized to some extent in housing, population density, crime and poverty, however, the vast majority of its inhabitants have access to basic amenities and most areas are connected to major roads and completely urbanized. Nevertheless, smaller settlements lacking these can still be found in the periphery of the city and its inhabitants are known as "paracaidistas". A more recent example of slum-upgrading approach is PRIMED initiative in [[Medellín]], Colombia, where streets, [[Metrocable (Medellín)|Metrocable]] transportation and other public infrastructure has been added. These slum infrastructure upgrades were combined with city infrastructure upgrade such as addition of metro, paved roads and highways to empower all city residents including the poor with reliable access throughout city.<ref>Fernando Patino,[http://www.unhabitat.org/pmss/listItemDetails.aspx?publicationID=3222BUILDING Urban Safety through Slum Upgrading] {{Webarchive|url=https://web.archive.org/web/20130921055007/http://www.unhabitat.org/pmss/listItemDetails.aspx?publicationID=3222BUILDING |date=2013-09-21}} United Nations Habitat (2011); {{ISBN|978-9211323931}}. pages 7–19.</ref>

Most slum upgrading projects, however, have produced mixed results. While initial evaluations were promising and success stories widely reported by media, evaluations done 5 to 10 years after a project completion have been disappointing. Herbert Werlin<ref name="werlin" /> notes that the initial benefits of slum upgrading efforts have been ephemeral. The slum upgrading projects in ''kampungs'' of Jakarta, Indonesia, for example, looked promising in first few years after upgrade, but thereafter returned to a condition worse than before, particularly in terms of sanitation, environmental problems and safety of drinking water. Communal toilets provided under slum upgrading effort were poorly maintained, and abandoned by slum residents of Jakarta.<ref>[http://siteresources.worldbank.org/INTEMPOWERMENT/Resources/10142_urban.pdf World Bank Experience with the Provision of Infrastructure Services for the Urban Poor] {{Webarchive|url=https://web.archive.org/web/20130921054354/http://siteresources.worldbank.org/INTEMPOWERMENT/Resources/10142_urban.pdf |date=2013-09-21}} Christine Kessides] The World Bank (1997)</ref> Similarly slum upgrading efforts in Philippines,<ref>Luna, E. M., Ferrer, O. P. and Ignacio, Jr., U. (1994) "Participatory Action Planning for the Development of Two PSF Projects". Manila: University of Philippines</ref><ref>Bartone, C., Bernstein, J., Leitmann, J. and Eigen, J. (1994) ''Toward Environmental Strategies for Cities''. Washington, D.C.: The World Bank.</ref>{{page needed|date=October 2024}} India<ref>Bannerjee, T. and Chakrovorty, S. (1994) "Transfer of planning technology and local political economy: a retrospective analysis of Calcutta", ''Journal of the American Planning Association'', 60, pages 71–82</ref> and Brazil<ref>{{cite journal |doi=10.1111/j.1467-8330.2011.00894.x |title=From Preamble to Post-project Frustrations: The Shaping of a Slum Upgrading Project in Recife, Brazil |journal=Antipode |volume=44 |pages=175–196 |year=2012 |last1=Koster |first1=Martijn |last2=Nuijten |first2=Monique|issue=1 |bibcode=2012Antip..44..175K }}</ref><ref>Smolka, M (2003), "Informality, urban poverty, and land market prices". ''Land Lines'' 15(1).</ref> have proven to be excessively more expensive than initially estimated, and the condition of the slums 10 years after completion of slum upgrading has been slum like. The anticipated benefits of slum upgrading, claims Werlin, have proven to be a myth.<ref name="werlin" /> There is limited but consistent evidence that slums upgrading may prevent diarrhoeal diseases and water-related expenditure.<ref>{{cite journal |vauthors=Turley R, Saith R, Bhan N, Rehfeuss E, Carter B |title=Slum Upgrading Strategies Involving Physical Environment and Infrastructure Interventions and Their Effects on Health and Socio-Economic Outcomes |journal=Cochrane Database of Systematic Reviews |date=January 2013 |issue=1 |article-number=CD010067 |doi=10.1002/14651858.CD010067.pub2 |pmid=23440845}}</ref>

Slum upgrading is largely a government controlled, funded and run process, rather than a competitive market driven process. Krueckeberg and Paulsen note<ref>[http://storage.globalcitizen.net/data/topic/knowledge/uploads/20121031115724997280_755_krueckeberg_paulsen_00.pdf "Urban Land Tenure Policies in Brazil, South Africa, and India: an Assessment of the Issues"] {{Webarchive|url=https://web.archive.org/web/20130921054731/http://storage.globalcitizen.net/data/topic/knowledge/uploads/20121031115724997280_755_krueckeberg_paulsen_00.pdf |date=2013-09-21}} Donald A. Krueckeberg and Kurt G. Paulsen (2000), Lincoln Institute, Rutgers University</ref> conflicting politics, government corruption and street violence in slum regularization process is part of the reality. Slum upgrading and tenure regularization also upgrade and regularize the slum bosses and political agendas, while threatening the influence and power of municipal officials and ministries. Slum upgrading does not address poverty, low paying jobs from informal economy, and other characteristics of slums.<ref name="Cavalcanti" />{{page needed|date=October 2024}} Recent research shows that the lack of these options make residents to undertake measures to assure their working needs.<ref name="CAVALCANTI 2017 71–81" /> One example in the northeast of Brazil, Vila S. Pedro, was mischaracterized by informal self-constructions by residents to restore working opportunities originally employed in the informal settlement.<ref name="Cavalcanti" />{{page needed|date=October 2024}} It is unclear whether slum upgrading can lead to long-term sustainable improvement to slums.<ref>Marie Huchzermeyer and Aly Karam, ''Informal settlements: A perpetual challenge?'' Cape Town, South Africa: University of Cape Town Press.</ref>{{Page needed|date=October 2024}}

===Urban infrastructure development and public housing===
[[File:StreetAlamosChalcoMX.jpg|thumb|Housing projects in [[Chalco de Díaz Covarrubias|Chalco]], Mexico]]
[[File:Minha Casa, Minha Vida em Eunápolis (Bahia).jpg|thumb|Housing projects in [[Eunápolis|Bahia]], Brazil]]
Urban infrastructure such as reliable high speed [[Public transport|mass transit]] systems, motorways/interstates, and public housing projects have been cited<ref>[http://www.fta.dot.gov/documents/Policy_and_Planning_as_Public_Choice.pdf "Policy and Planning as Public Choice Mass Transit in the United States"] {{Webarchive|url=https://web.archive.org/web/20130512230240/http://www.fta.dot.gov/documents/Policy_and_Planning_as_Public_Choice.pdf |date=2013-05-12}} Daniel Lewis and Fred Williams, Federal Transport Agency, DOT, US Government, 1999; Ashgate</ref><ref>{{cite journal |doi=10.1080/01944366208979438 |title=The Case for Scatteration: Some Reflections on the National Capital Region ''Plan'' for the Year 2000 |journal=Journal of the American Institute of Planners |volume=28 |issue=3 |pages=159–169 |year=1962 |last1=Lessinger |first1=Jack}}</ref> as responsible for the disappearance of major slums in the United States and Europe from the 1960s through 1970s. [[Charles Pearson]] argued in UK Parliament that mass transit would enable London to reduce slums and relocate slum dwellers. His proposal was initially rejected for lack of land and other reasons; but Pearson and others persisted with creative proposals such as building the mass transit under the major roads already in use and owned by the city. [[London Underground]] was born, and its expansion has been credited to reducing slums in respective cities<ref>[http://www.ltmcollection.org/resources/index.html?IXglossary=Public+transport+in+Victorian+London%3A+Part+Two%3A+Underground "Public transport in Victorian London: Part Two: Underground"] {{Webarchive|url=https://web.archive.org/web/20130531062231/http://www.ltmcollection.org/resources/index.html?IXglossary=Public+transport+in+Victorian+London%3a+Part+Two%3a+Underground |date=2013-05-31}} London Transport Museum (2010)</ref> (and to an extent, the [[New York City Subway]]'s smaller expansion).<ref>nycsubway.org—[http://www.nycsubway.org/wiki/The_Impact_of_the_IRT_on_New_York_City_(Hood) "Historic American Engineering Record: Clifton Hood, IRT and New York City, Subway"] {{Webarchive|url=https://web.archive.org/web/20130921053845/http://www.nycsubway.org/wiki/The_Impact_of_the_IRT_on_New_York_City_(Hood) |date=2013-09-21}}</ref>

As cities expanded and [[Business park|business parks]] scattered due to cost ineffectiveness, people moved to live in the suburbs; thus retail, logistics, house maintenance and other businesses followed demand patterns. City governments used infrastructure investments and urban planning to distribute work, housing, green areas, retail, schools and population densities. Affordable public mass transit in cities such as New York City, London and Paris allowed the poor to reach areas where they could earn a livelihood. Public and council housing projects cleared slums and provided more sanitary housing options than what existed before the 1950s.<ref>Sam Roberts (May 8, 2005). [https://www.nytimes.com/2005/05/08/nyregion/08housing.html?_r=0 "Before Public Housing, a City Life Cleared Away"] {{Webarchive|url=https://web.archive.org/web/20141216145710/http://www.nytimes.com/2005/05/08/nyregion/08housing.html?_r=0 |date=2014-12-16}} ''The New York Times''.</ref>

Slum clearance became a priority policy in Europe between 1950–1970s, and one of the biggest state-led programs. In the UK, the slum clearance effort was bigger in scale than the formation of [[British Railways]], the [[National Health Service]] and other state programs. UK Government data suggests the clearances that took place after 1955 demolished about 1.5 million slum properties, resettling about 15% of UK's population out of these properties.<ref>Becky Tunstall and Stuart Lowe (November 2012). [http://www.york.ac.uk/spsw/news-and-events/news/2012/breaking-up-communities/ "The impact of post-war slum clearance in the UK"] {{Webarchive|url=https://web.archive.org/web/20130921060457/http://www.york.ac.uk/spsw/news-and-events/news/2012/breaking-up-communities/ |date=2013-09-21}} ''Social Policy and Social Work''. The University of York.</ref> Similarly, after 1950, Denmark and others pursued parallel initiatives to clear slums and resettle the slum residents.<ref name="kbt2012" />

The US and European governments additionally created a procedure by which the poor could directly apply to the government for housing assistance, thus becoming a partner to identifying and meeting the housing needs of its citizens.<ref>[http://fet.uwe.ac.uk/conweb/house_ages/council_housing/section4.htm "Inter-war Slum Clearance"] {{Webarchive|url=https://web.archive.org/web/20130921053314/http://fet.uwe.ac.uk/conweb/house_ages/council_housing/section4.htm |date=2013-09-21}} The History of Council Housing; UK</ref><ref>[http://fet.uwe.ac.uk/conweb/house_ages/council_housing/section6.htm "A New Urban Vision"] {{Webarchive|url=https://web.archive.org/web/20130921053702/http://fet.uwe.ac.uk/conweb/house_ages/council_housing/section6.htm |date=2013-09-21}} UK's History of Council Housing (2008)</ref> One historically effective approach to reduce and prevent slums has been citywide infrastructure development combined with affordable, reliable public mass transport and public housing projects.<ref>{{cite journal |doi=10.1080/20450249.2013.11873887 |title=Can infrastructure prevent a planet of slums? |journal=Construction Research and Innovation |volume=4 |issue=2 |pages=30–33 |year=2017 |last1=Rogers |first1=David |s2cid=115791262}}</ref>

However, slum relocation in the name of urban development is criticized for uprooting communities without consultation or consideration of ongoing livelihood. For example, the Sabarmati Riverfront Project, a recreational development in Ahmedabad, India, forcefully relocated over 19,000 families from shacks along the river to 13 public housing complexes that were an average of 9&nbsp;km away from the family's original dwelling.<ref>{{cite journal |last1=Mathur |first1=Navdeep |date=December 1, 2012 |title=On the Sabarmati Riverfront: Urban Planning as Totalitarian Governance in Ahmedabad |journal=Economic and Political Weekly |volume=47 |issue=47/48 |pages=64–75 |jstor=41720411 |hdl=11718/13623}}</ref>

==Prevalence==
[[File:Urban population living in slums.svg|thumb|upright=1.3|Percent urban population of a country living in slums ([[UN Habitat]], 2005)]]
[[File:Urban population living in slums, OWID.svg|thumb|upright=1.3|Urban population living in slums, 2014.<ref>{{cite web |title=Urban population living in slums |url=https://ourworldindata.org/grapher/urban-slums-total |website=Our World in Data |access-date=March 6, 2020 |archive-url=https://web.archive.org/web/20200407025031/https://ourworldindata.org/grapher/urban-slums-total |archive-date=April 7, 2020 |url-status=live}}</ref>]]
Slums exist in many countries and have become a global phenomenon.<ref name="Working paper">{{cite journal |last=Arimah |first=Ben C. |title=The face of urban poverty: Explaining the prevalence of slums in developing countries |journal=World Institute for Development Economics Research |year=2010 |volume=30 |url=https://ideas.repec.org/p/unu/wpaper/wp2010-30.html |access-date=2018-10-11 |archive-url=https://web.archive.org/web/20181012053907/https://ideas.repec.org/p/unu/wpaper/wp2010-30.html |archive-date=2018-10-12 |url-status=live}}</ref> A UN-Habitat report states that in 2006 there were nearly 1 billion people settling in slum settlements in most cities of [[Central America]], [[Asia]], [[South America]] and [[Africa]], and a smaller number in the cities of [[Europe]] and [[North America]].<ref>{{cite book |author=[[United Nations Human Settlements Programme]] |title=State of the World's Cities 2006/2007: The Millennium Development Goals and Urban Sustainability |year=2006 |publisher=Earthscan |location=London}}</ref>{{page needed|date=October 2024}}

In 2012, according to UN-Habitat, about 863 million people in the [[developing world]] lived in slums. Of these, the urban slum population at mid-year was around 213 million in [[Sub-Saharan Africa]], 207 million in [[East Asia]], 201 million in [[South Asia]], 113 million in [[Latin America]] and [[Caribbean]], 80 million in [[Southeast Asia]], 36 million in [[West Asia]], and 13 million in [[North Africa]].<ref name="UNHABITATswcr1213">{{cite web |title=State of the World's Cities Report 2012/2013: Prosperity of Cities |publisher=UN-Habitat |url=http://sustainabledevelopment.un.org/content/documents/745habitat.pdf |access-date=October 4, 2013 |archive-url=https://web.archive.org/web/20131004233458/http://sustainabledevelopment.un.org/content/documents/745habitat.pdf |archive-date=October 4, 2013 |url-status=live}}</ref>{{rp|127}} Among individual countries, the proportion of urban residents living in slum areas in 2009 was highest in the [[Central African Republic]] (95.9%), [[Chad]] (89.3%), [[Niger]] (81.7%), and [[Mozambique]] (80.5%).<ref name="UNHABITATswcr1213" />

The distribution of slums within a city varies throughout the world. In most of the [[developed countries]], it is easier to distinguish the slum-areas and non-slum areas. In the United States, slum dwellers are usually in city neighborhoods and inner [[suburbs]], while in [[Europe]], they are more common in high rise housing on the urban outskirts. In many [[developing countries]], slums are prevalent as distributed pockets or as urban orbits of densely constructed informal settlements.<ref name="Working paper" />

In some cities, especially in countries in [[South Asia]] and [[Sub-Saharan Africa]], slums are not just marginalized neighborhoods holding a small population; slums are widespread, and are home to a large part of urban population. These are sometimes called ''slum cities''.<ref>{{cite book |title=Slum Cities and Cities with Slums" States of the World's Cities 2008/2009 |publisher=UN-Habitat}}</ref>{{page needed|date=October 2024}}

The percentage of developing world's urban population living in slums has been dropping with economic development, even while total urban population has been increasing. In 1990, 46 percent of the urban population lived in slums; by 2000, the percentage had dropped to 39%; which further dropped to 32% by 2010.<ref>{{cite web |title=State of the World's Cities Report 2012/2013: Prosperity of Cities |publisher=UN-Habitat |url=http://sustainabledevelopment.un.org/content/documents/745habitat.pdf |page=127 |access-date=2013-10-04 |archive-url=https://web.archive.org/web/20131004233458/http://sustainabledevelopment.un.org/content/documents/745habitat.pdf |archive-date=2013-10-04 |url-status=live}}</ref>

==See also==
* [[List of slums]]
* [[Informal waste collection]]

=== Variations of impoverished settlements ===
{{colbegin}}
* [[Banlieue]] (Term used for the deprived neighbourhoods in the edges or around the French cities)
* [[Barrio]] (slums in Venezuela)
* [[Campamento (Chile)|Campamento]] (slums in Chile)
* [[Favela]] (slums in Brazil)
* [[Gecekondu]] (slums in Turkey)
* [[Ghetto]]
* [[Hooverville]] (slums in 1930s US)
* [[Inner city]]
* [[Komboni]] (slums in Zambia)
* [[Pueblos jóvenes]] (slums in Peru)
* [[Refugee shelter]]
* [[Romani People]] camp
* [[Rooftop slum]]
* [[Rookery (slum)|Rookery]] (slums in London, United Kingdom)
* [[Shanty town]]
* [[Skid row]]
* [[Tent city]]
* [[Trailer park]]
* [[Urban village (China)]]
* [[Villa miseria]] (slums in Argentina)
{{colend}}

==References==
{{Reflist|30em}}

==Further reading==
{{Wiktionary}}
{{Commons category|Slums}}
* (2017). ''[https://maxwellhalsted.uic.edu/home/chicago-dark-grotesque-slum-lawless/story-of-the-slum Story of the Slum, Chicago West Side 1890-1930]''
* [[Michael Parenti|Parenti, Michael]] (January 2014). [http://www.michaelparenti.org/whats_a_slum.html "What's a Slum?"]
* {{cite book |title=The Challenge of Slums: Global Report on Human Settlements |url=http://www.unhabitat.org/content.asp?typeid=19&catid=555&cid=5373 |access-date=August 15, 2013 |publisher=UN-Habitat |isbn=978-1-1-36554-759 |archive-url=https://web.archive.org/web/20130602164354/http://www.unhabitat.org/content.asp?typeid=19&catid=555&cid=5373 |archive-date=June 2, 2013 |df=dmy-all |date=2012-05-23}} (original report 2003, revised 2010, reprint 2012)
* {{cite book |last=Moreno |first=Eduardo López |title=Slums of the World: The Face of Urban Poverty in the New Millennium? |url=https://archive.org/details/SlumsOfTheWorldTheFaceOfUrbanPovertyInTheNewMillennium |access-date=August 15, 2013 |year=2003 |publisher=UN-Habitat |isbn=978-92-1-131683-4}}
* [[Robert Neuwirth]]: ''Shadow Cities'', New York, 2006, Routledge
* [[Mike Davis (scholar)|Davis, Mike]]:''Planet of Slums'' London, New York 2006 {{ISBN|1-84467-022-8}}
* Cavalcanti, Ana Rosa Chagas(2017). "Work, Slums, and Informal Settlement Traditions: Architecture of the Favela Do Telegrafo". ''Traditional Dwellings and Settlements Review''. 28(2): 71–81.
* Cavalcanti, Ana Rosa Chagas. ''Housing Shaped by Labour: The Architecture of Scarcity in Informal Settlements''. Berlin, 2017, Jovis. 
* Elisabeth Blum / Peter Neitzke: ''FavelaMetropolis''. Berichte und Projekte aus Rio de Janeiro und São Paulo, Birkhäuser Basel, Boston, Berlin 2004 {{ISBN|3-7643-7063-7}}
* Floris Fabrizio ''Puppets or people? A sociological analysis of Korogocho slum'', Pauline Publication Africa, Nairobi 2007.
* Floris Fabrizio ''Eccessi di Città: Baraccopoli, campi profughi, città psichedeliche'', Paoline, Milano, {{ISBN|88-315-3318-5}}
* Matt Birkinshaw [http://www.abahlali.org/node/4013 "A Big Devil in the Jondolos: A report on shack fires"], 2008
* [https://www.theguardian.com/international/story/0,,1055785,00.html "Every third person will be a slum dweller within 30 years, UN agency warns"]; John Vidal; ''[[The Guardian]]''; October 4, 2003.
* [https://web.archive.org/web/20070227034515/http://www.metamute.org/en/Naked-Cities-Struggle-in-the-Global-Slums "Naked Cities – Struggle in the Global Slums"]. ''Mute Magazine'' Vol 2#3, 2006
* [http://www.citiesalliance.org Cities Alliance]
* {{cite journal |last1=Marx |first1=Benjamin |last2=Stoker |first2=Thomas |last3=Suri |first3=Tavneet |year=2013 |title=The Economics of Slums in the Developing World |journal=Journal of Economic Perspectives |volume=27 |issue=4 |pages=187–210 |doi=10.1257/jep.27.4.187 |doi-access=free}}

{{Authority control}}

[[Category:Slums| ]]
[[Category:Human habitats]]
[[Category:Urban decay]]
[[Category:Urban planning]]
[[Category:Types of populated places]]
[[Category:Urban geography]]