How Urban Slums Affect Environmental Sanitation

India’s cities are growing at a breathless pace, and a significant share of that growth is concentrated in informal settlements. Roughly 65 million people live in slums across India, often packed into narrow lanes with open drains, shared toilets, and uncollected garbage piling up at street corners. These conditions are not just an aesthetic concern – they fundamentally shape the environmental sanitation of entire neighbourhoods, and by extension, the health of millions. Understanding how slum environments interact with water, waste, and air is essential for anyone studying population and family health today.

What environmental sanitation really means 🔗

The World Health Organization defines environmental sanitation as the control of all factors in a person’s physical environment that may harm physical development, health, or survival. In practical terms, this covers drainage of rainwater and sewage, collection and disposal of garbage, removal of human excreta, and the quality of air and soil around homes. When even one of these systems fails, the others tend to collapse with it, and slums are where this chain reaction is most visible.

Slum settlements typically lack at least one of five basic amenities: durable housing, sufficient living space, access to clean water, improved sanitation, and secure land tenure. The absence of secure tenure is particularly damaging because municipalities are often reluctant to extend formal water and sewage lines to settlements they consider “illegal.” The result is a sanitation vacuum that residents must fill with informal, often unsafe, arrangements.

Contaminated drinking water and the disease burden 🔗

Drinking water in slums travels a difficult journey before it reaches a household. Pipes often run alongside or even through open drains, and frequent leakages allow sewage to seep into the supply. Where piped water is unavailable, residents depend on community taps, handpumps, or tankers – all of which are vulnerable to contamination during storage and handling.

A community-based study in the urban slums of Lucknow found that about 96.5% of families residing in kaccha slums practised open-field defecation, which directly pollutes nearby water sources. When untreated sewage meets drinking water, the consequences are predictable: up to 75% of India’s surface water is polluted, creating ideal breeding grounds for pathogens that cause cholera, dysentery, typhoid, and hepatitis.

Why children pay the highest price 🔗

Diarrhoeal disease is the most immediate consequence of contaminated water, and children under five carry the heaviest burden. UNICEF estimates that poor sanitation has contributed to nearly 100,000 diarrhoeal deaths of children under five years in India. A study in Kolkata’s slums found that children younger than five were 3.7 times more likely to suffer from diarrhoea than other age groups, with incidence rates among children under two crossing 270 cases per 1,000 person-years.

The damage is not limited to acute illness. Repeated episodes of diarrhoea in early childhood interfere with nutrient absorption, leading to stunting, wasting, and weakened immunity. This creates a vicious cycle: malnourished children fall ill more often, and each illness deepens their malnutrition.

Poor sanitation facilities and open defecation 🔗

Despite major national efforts under the Swachh Bharat Mission, toilet access in slums remains deeply uneven. Many households share a single toilet with several neighbours, and community toilet blocks are often poorly maintained, dimly lit, or located far from homes. For women and girls, these conditions translate into safety risks and a tendency to wait until dark, which can cause urinary tract infections and other health problems.

Research in Delhi’s slums has shown that inadequate infrastructure and overcrowded conditions remain the central barriers to adopting safe sanitation practices, even when residents are aware of the health risks. A survey in Lucknow’s slums recorded that 32% of respondents still engaged in open defecation, only 22% practised proper hand hygiene, and 40% lacked access to enough water for hygiene needs.

The geography of open defecation 🔗

Open defecation is often imagined as a rural problem, but urban slums tell a different story. When toilets are absent, broken, or unaffordable, residents use railway tracks, empty plots, riverbanks, and the edges of drains. A study in a South Indian slum found that sharing a sanitation facility with six or more households, proximity of toilets within 15 metres of homes, and the presence of faeces and flies around toilets were significantly associated with acute diarrhoea. In other words, even where toilets exist, poor maintenance and overcrowding can make them part of the problem rather than the solution.

Children’s stool disposal – an overlooked link 🔗

One of the most neglected aspects of slum sanitation is the disposal of young children’s faeces. Many caregivers throw soiled diapers or children’s stools into open drains or onto garbage piles, assuming children’s waste is less harmful. In reality, indiscriminate disposal of children’s stools is one of the maternal behaviours most strongly linked to childhood diarrhoea, and it directly seeds the environment with pathogens that affect the entire community.

Solid waste, air pollution, and environmental health 🔗

Municipal solid waste management is one of the obligatory functions of urban local bodies in India, but in slum areas the system rarely reaches the household level. Door-to-door collection is patchy, segregation at source is uncommon, and informal waste pickers – many of whom themselves live in slums – handle a significant share of what does get sorted, often without protective gear.

In urban kaccha slums in Lucknow, researchers documented that about 98.3% of families used indiscriminate throwing as their method of solid waste disposal. Garbage accumulates in open lots, drains, and along railway lines, where it attracts rodents and flies, blocks drainage during the monsoon, and breeds mosquitoes that spread dengue, chikungunya, and malaria.

Open burning and the air we breathe 🔗

When formal collection fails, residents often burn their garbage. The smoke contains particulate matter, volatile organic compounds, dioxins, and furans – a mix that aggravates asthma, bronchitis, and other respiratory conditions. In communities living near landfills such as Delhi’s Ghazipur site, the stench and smoke from uncollected waste have been linked to a rising burden of cardiac and respiratory diseases. Indoor air quality also suffers, since many slum households still rely on kerosene, biomass, or charcoal for cooking, releasing pollutants into poorly ventilated single-room homes.

Soil contamination and the nutrition link 🔗

Soil in and around slums is regularly contaminated by leachate from waste piles, chemicals from informal industries, and faecal matter from open defecation. Children playing barefoot ingest pathogens through their hands, leading to repeated intestinal infections and parasitic worm loads. Combined with limited dietary diversity, this contributes to the high rates of stunting and malnutrition observed in slum populations, with water, sanitation, and hygiene practices being closely associated with child linear growth.

Why the problem persists 🔗

Several structural reasons explain why slum sanitation remains stubbornly poor even after decades of urban policy. Land tenure insecurity discourages investment in permanent infrastructure. Population density makes it physically difficult to lay sewer lines and place individual toilets. Municipal budgets are stretched thin, and slum-specific data is often missing from official planning documents.

The Swachh Bharat Mission has made real progress – the number of people defecating in the open in India has reduced by an estimated 450 million people – but inequities persist within cities. Inside slums, where population densities are highest and structural vulnerabilities deepest, levels of morbidity and mortality from water- and sanitation-related diseases remain unacceptably high.

Pathways to better slum sanitation 🔗

Improving environmental sanitation in slums requires more than building toilets. It requires a coordinated approach: legalising tenure so families can invest in their homes, designing decentralised sewage and faecal sludge management systems, integrating informal waste pickers into formal collection networks, and running sustained behaviour change campaigns around handwashing, child stool disposal, and water storage.

Equally important is recognising that slum residents are not passive victims of poor sanitation. They are the first responders, the rag pickers, the masons, and the community health workers who make cities function. Any sanitation programme that ignores their knowledge and labour will struggle to deliver lasting results.

What do you think? If you had to choose one intervention – better toilets, cleaner drinking water, or improved waste collection – to begin transforming sanitation in an urban slum, which would you prioritise and why? And how should city governments balance the rights of slum residents to basic services with debates over land tenure and urban planning?

References

1. https://earth5r.org/waste-management-for-slums-earth5r/
2. https://www.researchgate.net/publication/384326263_EXPLORING_THE_SOCIAL_AND_ENVIRONMENTAL_FACTORS_INFLUENCING_HYGIENE_PRACTICES_IN_AN_URBAN_SLUM_LUCKNOW
3. https://pmc.ncbi.nlm.nih.gov/articles/PMC10434291/
4. https://www.canr.msu.edu/news/india-the-problem-of-open-defecation
5. https://www.unicef.org/india/what-we-do/water-sanitation-hygiene
6. https://academic.oup.com/jid/article/224/Supplement_5/S573/6433799
7. https://link.springer.com/article/10.1007/s40899-024-01046-x
8. https://www.researchgate.net/publication/327833504_Solid_Waste_Disposal_practices_in_an_Urban_Slum_Area_of_South_India
9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5217632/
10. https://borgenproject.org/indias-waste-management/
11. https://pmc.ncbi.nlm.nih.gov/articles/PMC5020240/