Open waste burning in Indian cities triples in winter, finds WRI India study
It adds under 1% of a city's PM2.5, yet poor neighbourhoods breathe its smoke. Why does winter make it worse?
Published 10 September 2026. Written by Pratidin from the reports linked at the end; every fact checked by a separate review before publishing. How we work
A study by WRI India, reported by The Hindu on 10 September 2026, has found that open burning of waste in Indian cities triples in winter compared with summer. The study covered 11 polluted Indian cities from 2019 to 2026. Tier 2 cities recorded the largest quantities of waste burned, while Tier 3 cities showed the highest winter incidence, averaging 49.6 burning incidents per square kilometre per day. Poorer areas in Tier 2 cities recorded the highest incidence of all, nearly 84 incidents per square kilometre per day. The study found a strong association between higher burning and poorer socio-economic areas, which it read as a sign of disparities in municipal services. WRI India describes itself as an independent charity focused on environmentally sound and socially equitable development.
Open waste burning contributes less than 1% of total citywide emissions of PM2.5 and PM10, fine and coarse particulate matter of diameter up to 2.5 and 10 micrometres. But it sharply increases short-term exposure to toxic smoke close to homes and waste dumps, because the smoke is released at ground level. The winter rise is made worse by falling temperatures and stagnant atmospheric conditions that hinder the dispersion of pollutants, a pattern linked to temperature inversions, when warmer air sits over cooler air near the ground. Burning waste releases dioxins, furans, heavy metals and volatile organic compounds, which cause respiratory disorders and heart disease and raise cancer risks.
The findings matter for how clean-air policy is designed. Programmes that rank pollution sources by their citywide share can miss sources whose harm is concentrated in particular neighbourhoods and seasons. The study's tiers follow common population bands: Tier 1 cities above 10 lakh people, Tier 2 between 5 lakh and 10 lakh, and Tier 3 between 1 lakh and 5 lakh. Waste collection is the responsibility of urban local bodies, which received constitutional status through the 74th Constitutional Amendment, in force from 1 June 1993. The study reads the link with poorer areas as a sign of inequities in waste collection and management.
Prelims facts
- A WRI India study of 11 polluted cities (2019 to 2026) found open waste burning triples in winter compared with summer.
- Open waste burning contributes less than 1% of citywide PM2.5 and PM10 emissions but raises short-term exposure near homes and dumps.
- Poorer areas in Tier 2 cities recorded the highest incidence, nearly 84 incidents per square kilometre per day; Tier 3 cities averaged 49.6 in winter.
- Burning waste releases dioxins, furans, heavy metals and volatile organic compounds.
- Winter burning is worsened by falling temperatures and stagnant air that hinder the dispersion of pollutants.
Quick recall
- Which organisation conducted the study on open waste burning in Indian cities reported on 10 September 2026?
- WRI India.
- How many cities and which years did the study cover?
- 11 polluted cities, from 2019 to 2026.
- How much does open waste burning rise in winter compared with summer?
- About three times.
- Share of open waste burning in citywide PM2.5 and PM10 emissions
- Less than 1%.
- Highest burning incidence recorded in the study
- Nearly 84 incidents per square kilometre per day, in poorer areas of Tier 2 cities.
- What is PM2.5?
- Particulate matter with a diameter of 2.5 micrometres or less.
- WHO 2021 annual guideline value for PM2.5
- 5 µg/m3 (24-hour: 15 µg/m3).
- When did the 74th Constitutional Amendment come into force?
- 1 June 1993.
Prelims practice question
Why does smoke from ground-level sources such as open waste burning tend to stay close to the ground in north Indian cities on winter nights?
- Because humidity converts all smoke particles into rain
- Because strong winter winds push smoke downwards
- Because a layer of warmer air above cooler surface air suppresses vertical mixing
- Because the ozone layer is thinner in winter
Show answer
Answer: (c) Because a layer of warmer air above cooler surface air suppresses vertical mixing. On clear winter nights the ground loses heat by radiation, cooling the air next to it while warmer air remains above. This temperature inversion stops pollutants from rising and dispersing. The other options do not describe the mechanism.
Use this in UPSC Mains: previous-year questions
Recurring theme: Urban air pollution: sources, exposure, standards and the role of city governments in clean-air action.
- How to use this
The WRI India study exposes a gap in clean-air planning that ranks sources by citywide share, supporting a call for neighbourhood-level and seasonal action.
- A WRI India study of 11 polluted cities (2019 to 2026) found open waste burning triples in winter, though it contributes under 1% of citywide PM2.5 and PM10.
- Ground-level smoke near homes and dumps releases dioxins, furans, heavy metals and VOCs; poorer areas of Tier 2 cities recorded nearly 84 incidents per sq km per day.
- Suggested fixes: daily door-to-door collection in underserved areas by urban local bodies, winter hotspot mapping, and neighbourhood-level data in city clean-air plans.
The WHO's 2021 PM2.5 guidelines (5 µg/m3 annual, 15 µg/m3 24-hour) set the benchmark against which winter spikes from burning and inversions should be judged.
Mains practice question
Open burning of waste adds little to a city's total particulate emissions but much to the exposure of its poorest residents. Discuss, and suggest measures for urban local bodies. (150 words)
Model answer
A WRI India study of 11 polluted cities (2019 to 2026) found that open waste burning triples in winter and is concentrated in poorer areas, though it contributes less than 1% of citywide PM2.5 and PM10.
Why a small share matters
- Ground-level release: smoke is emitted beside homes and dumps, raising short-term exposure.
- Winter inversion: stagnant air traps smoke near the ground.
- Toxic mix: dioxins, furans, heavy metals and volatile organic compounds raise respiratory, heart and cancer risks.
- Inequity: poorer areas of Tier 2 cities recorded nearly 84 incidents per sq km per day.
Measures for urban local bodies
- Daily door-to-door collection in underserved areas first.
- Segregation and local processing to shrink dumps.
- Winter hotspot mapping and quick response.
- Neighbourhood-level data in city clean-air plans.
Clean air plans must count people exposed, not just tonnes emitted.
The basics
Why this matters
A heap of garbage set on fire at a street corner looks like a small, local nuisance. A study by WRI India shows it is a seasonal and social pattern: burning triples in winter and clusters in poorer neighbourhoods. The story connects three static ideas that UPSC tests often: what particulate matter is, why winter traps pollution, and who is responsible for city waste.
What the study found
The study covered 11 polluted Indian cities from 2019 to 2026. It classified them by size, as reported: Tier 1 cities with populations above 10 lakh, Tier 2 cities with 5 lakh to 10 lakh, and Tier 3 cities with 1 lakh to 5 lakh.
Small share, big exposure
Open burning adds less than 1% of total citywide emissions of PM2.5 and PM10. Yet the smoke is released at ground level, close to homes and waste dumps, so the people living nearby breathe far more of it than the city average suggests. See Particulate matter for what these particles do inside the body, and Toxins from burning waste for what else the smoke carries.
Why winter makes it worse
The study links the winter surge to falling temperatures and stagnant atmospheric conditions that hinder the dispersion of pollutants. On cold, still nights the ground loses heat quickly, cooling the air next to it, while warmer air sits above. This Temperature inversion acts like a lid, so smoke that would normally rise and disperse stays near the ground.
- 1Gaps in municipal collection are greatest in poorer areas
- 2Burning rises as temperatures fall
- 3Still, layered air keeps pollutants near the ground
- 4Residents near dumps and homes breathe the smoke
- 5Respiratory and heart disease and cancer risk add to pressure on services
Whose job is it
City waste is managed by urban local bodies, whose place in the Constitution was set by the 74th Constitutional Amendment. The study's finding that burning is strongly associated with poorer socio-economic areas points to unequal municipal services. The study reads the pattern as a sign of inequities in waste collection and management.
Go deeper
In one line: A WRI India study of 11 cities finds that open burning of waste triples in winter and is concentrated in poorer areas, adding little to citywide PM2.5 but a lot to local exposure.
Why it matters for UPSC
Air pollution, urban solid waste and environmental justice appear across GS3 (pollution) and GS1 (urbanisation). Prelims tests the science of particulates and inversions. Mains asks why clean-air programmes miss local hotspots and what urban local bodies must do.
The core idea
Burning waste releases Particulate matter and Toxins from burning waste at ground level. In winter, a Temperature inversion holds this smoke close to where people live. The burning itself reflects gaps in waste collection by urban local bodies, empowered by the 74th Constitutional Amendment, and those gaps are widest in poorer neighbourhoods.
Numbers and dates to remember
- 11 polluted cities studied, 2019 to 2026.
- Burning in winter about three times the summer level.
- Less than 1% of citywide PM2.5 and PM10 emissions come from open waste burning.
- 49.6 incidents per sq km per day: winter average in Tier 3 cities.
- Nearly 84 incidents per sq km per day: poorer areas of Tier 2 cities.
- WHO 2021 guideline for PM2.5: annual mean 5 µg/m3, 24-hour mean 15 µg/m3.
Where to go next
- Particulate matter: what PM2.5 and PM10 are and why size matters.
- Temperature inversion: why winter air traps smoke.
- Toxins from burning waste: dioxins, furans and other harmful emissions.
- 74th Constitutional Amendment: the basis of city governments that manage waste.
Go deeper: why a less than 1% source still matters
Clean-air policy usually ranks sources by their share of citywide emissions. On that ranking, open waste burning, at less than 1% of PM2.5 and PM10, looks minor next to vehicles, industry, construction dust or crop residue. The WRI India findings show why that ranking can mislead. Exposure depends on where and when pollution is released. Smoke from burning waste is emitted at ground level beside homes and dumps, and in winter a Temperature inversion keeps it there. A small source can therefore produce high short-term doses for the people nearby.
The second lesson is about equity. Burning incidents were strongly associated with poorer socio-economic areas, and poorer parts of Tier 2 cities recorded nearly 84 incidents per square kilometre per day. That pattern points to gaps in municipal collection rather than individual carelessness. Residents who are left without collection burn waste, and they and their neighbours then breathe Particulate matter laced with Toxins from burning waste.
Responsibility rests largely with city governments, whose constitutional basis is the 74th Constitutional Amendment. The policy options are familiar: regular door-to-door collection, segregation and processing of waste, clearing of legacy dumps and local monitoring of hotspots in winter. The study's contribution is to show that city averages should be read alongside neighbourhood data, so that the poorest areas are not left out of clean-air plans.
Particulate matter
The pollutant whose citywide share hides local harm.
In one line: Particulate matter is a mix of tiny solid and liquid particles in the air, classed by size as PM10 (10 micrometres or less) and PM2.5 (2.5 micrometres or less).
Why size matters
Coarser PM10 particles lodge in the nose and throat. Fine PM2.5 particles can penetrate deep into the lungs, reaching the bronchioles and alveoli, and some can cross into the bloodstream and travel through the body. That is why PM2.5 is linked to heart as well as lung disease.
Standards and the news
The World Health Organization's 2021 guidelines say PM2.5 should not exceed an annual mean of 5 µg/m3 or a 24-hour mean of 15 µg/m3. Indian cities often exceed these many times over in winter. The WRI India study found open waste burning adds less than 1% to citywide PM2.5 and PM10 but raises short-term exposure close to where it happens.
Where to go next
Temperature inversion
The reason winter smoke stays at ground level.
In one line: A temperature inversion is a layer of warmer air sitting over cooler air, the reverse of the normal pattern, and it traps pollution near the ground.
How it forms
Normally air gets cooler with height, so warm air near the surface rises and carries pollutants up and away. An inversion forms when the ground loses more heat by radiation than it receives from the sun, which happens at night and in winter when the sun is low. The air next to the ground cools, warmer air remains above, and vertical mixing stops.
Why it is in the news
The WRI India study links the winter rise in waste burning to falling temperatures and stagnant atmospheric conditions that hinder dispersion. Inversions are also why north Indian cities see their worst smog in winter, whatever the source.
Where to go next
Toxins from burning waste
What the smoke carries besides particles.
In one line: Burning mixed urban waste, which often includes plastics, releases dioxins, furans, heavy metals and volatile organic compounds along with particles.
What they are
Dioxins and furans are groups of highly toxic chlorinated compounds formed when materials containing chlorine burn at low temperatures, as in an open heap. Heavy metals such as lead and mercury are carried in the smoke and ash. Volatile organic compounds are carbon-based chemicals that evaporate easily and help form ground-level ozone.
Why it is in the news
The study notes that these substances cause respiratory disorders and heart disease and raise cancer risks. Because open burning happens at ground level near homes and dumps, people living nearby, often in poorer areas, receive the highest doses.
Where to go next
74th Constitutional Amendment
The constitutional basis of the city governments that must collect waste.
In one line: The 74th Constitutional Amendment gave constitutional status to urban local bodies such as municipal corporations and municipalities, and came into force on 1 June 1993.
What it did
The amendment made elected urban local bodies a constitutional requirement, with regular elections and a list of functions that State legislatures may devolve to them. Urban local bodies provide basic services, including waste management, water supply and sanitation. Their performance depends on how much money, staff and power each State actually hands over.
Why it is in the news
The WRI India study found a strong link between burning and poorer areas, pointing to disparities in municipal services. Where collection is irregular, residents burn waste. Closing that gap is a task for city governments, which is why the amendment's promise of empowered local bodies matters to clean air.
Where to go next
Take the 10 September 2026 quiz: 30 Prelims-style questions with answers