What Are Urban Slums? Understanding Concepts and Characteristics

Walk through almost any major Indian city and you will notice two parallel worlds existing side by side. On one side stand glass towers, malls, and gated colonies. On the other, tightly packed tin-roofed homes stretch across narrow lanes, often within a stone’s throw of the same skyline. These dense, under-served settlements are what we commonly call urban slums, and they are home to nearly one in four people living in cities across the developing world. Understanding what a slum truly is, how it is defined, and what makes life inside one different from the rest of the city is the first step toward thinking seriously about urban poverty, housing rights, and public health.

Defining urban slums 🔗

The word “slum” gets thrown around loosely in everyday conversation, but in policy and research it has a fairly specific meaning. The most widely accepted international definition comes from UN-HABITAT, the United Nations Human Settlements Programme. According to this framework, a slum household is a group of people living under the same roof in an urban area who lack one or more of five basic conditions.

The five UN-HABITAT criteria 🔗

The operational definition, agreed upon at a UN expert group meeting held in Nairobi in 2002, identifies a slum settlement through the combined absence of these features: inadequate access to safe water, inadequate access to sanitation and other infrastructure, poor structural quality of housing, overcrowding, and insecure residential status. A household does not need to be missing all five to be considered part of a slum. Even one deprivation is enough. The more conditions a household lacks, the more severe the deprivation.

It is worth noting what this definition deliberately leaves out. It focuses on physical and legal conditions, not on the people themselves. Slum residents are not defined by behaviour, caste, religion, or income alone. A community can be poor without being a slum, and a slum is not simply a synonym for poverty. It is the layering of multiple shelter deprivations that distinguishes a slum from other low-income neighbourhoods.

How India defines slums 🔗

India uses its own working definition for census and policy purposes. The Census of India recognises three categories of slums: notified, recognised, and identified. Notified slums are areas formally declared as slums by a state government or local body under a Slum Act. Recognised slums are those acknowledged by housing boards or municipal authorities but not formally notified. Identified slums are compact areas of at least 300 people or roughly 60-70 households living in poorly built, congested tenements with inadequate sanitation and drinking water.

This three-way classification matters because notification gives residents legal claims to services like piped water and sanitation, while un-notified or identified slums often remain invisible in municipal planning, even though they may hold the largest share of slum dwellers.

Characteristics of urban slums 🔗

Slums vary enormously from one country to another, and even from one neighbourhood to the next within the same city. But certain features recur often enough that they form a recognisable pattern.

Inadequate and unsafe housing 🔗

Houses in slums are typically built by residents themselves, using whatever materials they can afford or salvage. Walls may be made of brick, mud, tin sheets, plastic, or scrap wood. Roofs are often tarpaulin, asbestos, or corrugated metal. These structures are usually not designed to withstand heavy rain, floods, or fire, and they rarely comply with municipal building codes.

Overcrowding and lack of living space 🔗

Sufficient living space is one of the five UN-HABITAT criteria precisely because slum homes are routinely cramped. The benchmark is no more than three people per habitable room. In reality, many slum households fall far short of this. In Kibera, the largest informal settlement in Nairobi, eight or more people often share shacks rarely larger than 12 square metres. In parts of Mumbai, single-room dwellings serve as kitchen, bedroom, and living room for entire families.

Poor water and sanitation 🔗

Access to clean drinking water is irregular, and shared standpipes may serve hundreds of households. Toilets, where they exist, are typically community facilities with long queues. Open drains run beside footpaths, and human waste often mixes with stormwater. These conditions create breeding grounds for waterborne diseases like diarrhoea, cholera, and typhoid, and contribute to high rates of respiratory infections among children.

Insecure tenure 🔗

Many slum residents do not own the land they live on. They may be squatters, informal renters, or tenants of small landlords who themselves have no legal claim to the property. This insecurity hangs over daily life. A bulldozer can arrive with little notice. Investments in improving one’s home feel risky when eviction is always possible. In Kibera, for instance, the government formally owns all the land, and about 90 per cent of residents are tenants with no rights, paying rent to shack owners who themselves often hold no legal title.

Limited access to essential services 🔗

Beyond water and sanitation, slums tend to be cut off from formal infrastructure: paved roads, street lighting, garbage collection, electricity, schools, and health clinics. Where services do exist, they are often informal, irregular, or expensive. Electricity may be drawn through unauthorised connections, and waste management is frequently left to residents themselves.

Social and economic features 🔗

Slums are usually populated by rural migrants who came to the city in search of work and could not afford formal housing. Most residents work in the informal economy: as domestic workers, construction labourers, street vendors, recyclers, drivers, or small artisans. Incomes are low and irregular. Living in a slum is the reality for between 900 million and 1.6 billion people globally, amounting to about a quarter of the world’s urban population.

Reports of higher crime rates in slums often appear in media coverage, but researchers caution that this picture is incomplete. Crime in slums is shaped less by the residents themselves than by the absence of policing, lighting, and formal grievance systems. Many slums are also remarkable for their strong community networks, mutual aid arrangements, and vibrant local economies.

Global slum population statistics 🔗

The global slum population is enormous and unevenly distributed. UN-HABITAT estimated that around 881 million people lived in slums in 2014, which was just under a third of all urban dwellers in the developing world. Sub-Saharan Africa carries the heaviest burden, with more than half of its urban population living in slum conditions, compared with figures ranging between 20 and 31 per cent in other developing regions.

South Asia and India 🔗

India has one of the largest slum populations in the world in absolute terms. According to estimates, around 104 million people live in slums across India, roughly 9 per cent of the country’s population. Pakistan, Bangladesh, and Nepal also have significant slum populations, with Karachi’s Orangi Town often described as one of the largest informal settlements in Asia.

Africa: Kibera as a case study 🔗

Kibera, on the south-western edge of Nairobi, is one of the most studied slums in the world. The 2009 Kenya Population and Housing Census recorded Kibera’s population at 170,070, although earlier estimates ranged into the hundreds of thousands or even over a million. Its origins go back to 1912, when the British colonial administration allowed Sudanese-born soldiers to live in a forest outside Nairobi without ever granting them ownership of the land. Today, Kibera is known for severe infrastructure gaps but also for strong community-led initiatives.

India: Dharavi as a case study 🔗

Dharavi in Mumbai is perhaps the most internationally recognised slum, thanks in part to films set there. It sits on roughly 2.1 square kilometres of land and is home to about one million people, making it one of the most densely populated areas in the world. What sets Dharavi apart is its economy. It hosts thousands of small enterprises in leather goods, textiles, pottery, and especially recycling, with an estimated annual turnover that runs into hundreds of millions of dollars. Dharavi is a reminder that slums are not just sites of poverty but also productive engines of the urban economy, often subsidising the rest of the city with cheap labour and recycled materials.

Latin America 🔗

Latin American slums, locally known as favelas in Brazil, villas miserias in Argentina, or barrios in much of the region, often climb steep hillsides on the outskirts of cities like Rio de Janeiro, São Paulo, and Caracas. Compared with Sub-Saharan Africa, a smaller share of Latin America’s urban population lives in slums, but the absolute numbers remain large and the inequalities are stark.

Why understanding slums matters 🔗

Slums are not accidents. They are produced by the way cities grow: by rural distress that pushes migrants toward urban areas, by housing markets that cannot supply affordable homes, by planning systems that exclude the poor, and by colonial and political histories that shaped land ownership long ago. Treating slums as a public health, planning, and human rights issue requires moving past the idea that they are simply eyesores to be demolished. Many slum communities have lived on the same land for generations, built thriving informal economies, and asked little of the state beyond recognition and basic services.

What do you think? Should Indian cities focus on relocating slum residents into formal housing, or on upgrading existing settlements with secure tenure and better services? And how should we weigh the economic contribution of places like Dharavi when planning the future of our cities?

References

1. https://unhabitat.org/sites/default/files/2020/06/indicator_11.1.1_training_module_adequate_housing_and_slum_upgrading.pdf
2. https://unstats.un.org/sdgs/metadata/files/Metadata-11-01-01.pdf
3. https://arthapedia.in/index.php?title=Slums
4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6445475/
5. https://www.wearewater.org/en/kibera-the-slum-as-a-symptom_340571
6. https://www.kibera.org.uk/facts-info/
7. https://www.concern.org.uk/news/kibera-look-inside-africas-largest-slum
8. https://worldpopulationreview.com/cities/india/mumbai
9. https://en.wikipedia.org/wiki/Kibera
10. https://en.wikipedia.org/wiki/Dharavi