Delhi’s Toxic Winter Air Is Back as Pollution Soars Ahead of Diwali

Delhi’s air pollution is back. Just days after the Indian capital recorded its cleanest October in eight years, a thick grey haze has settled over the city, the air quality index has shot into the “very poor” range, and emergency pollution controls are in force again — all just as millions of people prepare to celebrate Diwali.

The return of the smog is an annual event that Delhi’s 30 million-plus residents know all too well. But this year the city government says it started preparing earlier than ever before, with a four-month Winter Action Plan that began on 1 November. The question now, as the festival weekend approaches, is whether early planning will be enough — or whether Delhi is heading for another winter of choking air.

How bad is the air right now?

The numbers tell the story of a very fast collapse. On Saturday 31 October, Delhi’s average air quality index (AQI) stood at 117, in the “moderate” band. By Sunday it had risen to 261. On Monday it reached 324, and on Tuesday 3 November it hit 350 — the worst reading in 287 days. The last time the city recorded worse air was on 20 January, when the index stood at 378.

On Wednesday morning the reading was 377, according to the BBC, and conditions were still deteriorating. Of the 57 monitoring stations reporting across the city on Tuesday, 10 were in the “severe” band, 35 in “very poor” and only 12 in “poor”. The worst readings were at Jahangirpuri, which touched 462, followed by Punjabi Bagh at 445, Rohini at 442 and the Delhi Technological University campus at 438.

India’s Central Pollution Control Board uses a scale where 0 to 50 is good, 51 to 100 is satisfactory, 101 to 200 is moderate, 201 to 300 is poor, 301 to 400 is very poor and 401 to 500 is severe. Delhi has now spent several days in the very poor band, with some neighbourhoods crossing into severe.

The main pollutant is PM2.5 — tiny particles about 30 times smaller than the width of a human hair. They are the most dangerous part of the smog because they are small enough to travel deep into the lungs and even into the bloodstream. The World Health Organization recommends that average PM2.5 levels over 24 hours should not go above 15 micrograms per cubic metre. During Delhi’s pollution season, levels are often more than 25 times that limit.

Why does Delhi’s air turn toxic every winter?

There is no single cause. Delhi’s winter smog is the result of several problems arriving at the same time — and winter weather makes all of them worse.

First, the weather itself. As temperatures fall and winds slow down, a layer of cold air traps pollutants close to the ground instead of letting them rise and disperse. Scientists call this a temperature inversion, and it is one of the main reasons northern India’s air gets so much worse in November and December. The first two weeks of November are usually the worst period of the year.

Second, smoke from burning crop stubble. Every autumn, farmers in Punjab and Haryana burn the leftover stalks from their rice harvest to clear their fields quickly for the next crop. The smoke drifts towards Delhi on north-westerly winds. Official estimates show how fast this source has grown in recent days: stubble burning accounted for 8.58% of Delhi’s PM2.5 on 2 November, 15.3% on 3 November, and was forecast to reach 20.1% on 4 November and 22.2% on 5 November. Satellites detected 219 farm fires across six northern and central states on 2 November alone, including 98 in Punjab, 67 in Rajasthan and 48 in Madhya Pradesh.

Third, the city’s own everyday emissions. Vehicle exhaust, dust from roads and construction sites, factory emissions and the open burning of waste all add to the load. Road dust is a bigger problem than many people realise: every passing vehicle lifts dust that can contain harmful chemicals, metals and tiny particles from tyres.

And fourth, the festival season. Diwali, one of India’s biggest festivals, falls this weekend. Fireworks release fine particles and harmful gases into the air, and in past years they have pushed pollution sharply higher for a night or two. This year India’s Supreme Court has allowed only certified “green” firecrackers, for limited hours on 7 and 8 November, with fireworks banned within 300 metres of hospitals and schools.

What makes this year’s spike so striking is how sudden it was. October had been unusually clean — Delhi recorded its lowest average AQI for the month in eight years, helped by rain and strong winds from a storm that washed pollutants out of the air. As the weather calmed, the north-westerly winds returned, carrying smoke from burning fields towards the capital, and the pollution came back within days.

What the government is doing

Delhi’s government says it acted earlier than usual this year. Its Winter Action Plan was announced months before the worst of the smog arrived and runs from 1 November to 28 February, covering the months when pollution usually spikes.

The plan restricts the entry of older, more polluting vehicles registered outside Delhi, and denies fuel to vehicles that cannot show a certificate proving they meet emission standards. Demolition work and outdoor construction that generates dust have been temporarily banned.

Alongside the winter plan sits the Graded Response Action Plan, known as GRAP, which is overseen by the federal Commission for Air Quality Management. GRAP introduces restrictions in stages, with stricter measures kicking in as pollution rises. Stage I covers the “poor” band of 201 to 300 and has been in force since 21 October. Stage II, for the “very poor” band of 301 to 400, was invoked on 2 November after the index reached 324. Stage III applies to the “severe” band of 401 to 450, and Stage IV to anything above 450.

Under Stage II, the use of diesel generators is restricted and the burning of coal and firewood is banned. Authorities have also stepped up street cleaning, raised parking fees to encourage people to use public transport, added 20 extra train services on weekdays and adjusted government working hours to ease traffic congestion.

Is the capital prepared?

Experts have welcomed the earlier start to the winter plan, but they caution that an early start alone will not be enough. Parthaa Bosu, a strategic adviser at the Environmental Defense Fund, put it bluntly: planning has improved a great deal, but execution still stands at roughly the same level as before.

That gap between plans and results is the central problem. Delhi has had winter action plans and graded emergency measures for years, yet the smog returns every winter. The measures target vehicles, dust and construction, but experts say restricting vehicles alone will not solve the problem while road dust, factory emissions, waste burning and smoke from farm fires continue.

Tackling pollution was a campaign promise of the governing Bharatiya Janata Party during last year’s election, and the winter plan is now a major test of that pledge. With the festival weekend approaching and the forecast pointing to very poor air from 4 to 6 November, followed by a fluctuation between very poor and severe over the following six days, the next week will show how much the early planning is worth.

The Pakistan connection

Delhi’s smog does not stop at borders, and neither do its causes. Satellite data from NASA’s Fire Information for Resource Management System shows that farm fires are burning on both sides of the frontier. Between 1 and 29 October, Pakistan’s Punjab recorded 13,241 agricultural fire detections, compared with 3,158 in India’s Punjab.

The comparison is not a simple one — the two provinces differ in size and farming patterns, and fires in Pakistan’s Punjab do not all blow towards Delhi. But the figures underline that stubble burning is a regional problem, not a local one. Lahore, just across the border, faces its own severe smog season every winter, and the same weather patterns that trap pollution over Delhi trap it over Lahore too. Any lasting solution will need action on both sides of the border, as well as in the Indian states around the capital.

What it means for people’s health

For Delhi’s residents, the smog is not an abstract problem. People complain of stinging eyes and difficulty breathing, and coughs and sneezes can be heard everywhere. For households that can afford them, air purifiers have become a necessity. Outdoors, people wear masks or cover their faces with cloth.

The people most at risk are children, older adults, and people with asthma or heart disease. Prolonged exposure to air at very poor levels can cause breathing problems and make existing illnesses worse.

The long-term cost is even starker. A 2025 report by the Energy Policy Institute at the University of Chicago estimated that air pollution could reduce life expectancy in Delhi by up to 8.2 years. On particularly bad days, monitoring stations in the city frequently record readings above 300, and on the worst days they can reach 500 — the top of India’s scale, which is a ceiling on the measuring system rather than on the pollution itself. International trackers have recorded readings close to 1,000 on some days, using a different scale.

What happens next

The immediate outlook is not good. The early warning system of the Indian Institute of Tropical Meteorology forecast very poor air from 4 to 6 November, then a fluctuation between very poor and severe over the following six days. Diwali fireworks this weekend are expected to add to the load, even with the restrictions on green firecrackers.

There is one hope on the horizon: a western disturbance — a weather system that brings rain and stronger winds — could clear the air, as the October storm did. But no such system is guaranteed, and until the winds change, the smoke from the fields and the dust from the city will keep building up under the cold, still winter air.

For now, Delhi’s residents are doing what they do every year: checking the air quality index each morning, keeping children indoors when the air is at its worst, and waiting for the wind to change.

Frequently asked questions

How bad is Delhi’s air right now?

Delhi’s average air quality index reached 350 on Tuesday 3 November, the worst reading in 287 days, and stood at 377 on Wednesday morning. Readings of 301 to 400 are classed as “very poor” in India, and some monitoring stations have crossed 450, into the “severe” band.

What is GRAP?

The Graded Response Action Plan is a set of emergency pollution measures for Delhi and the surrounding National Capital Region, overseen by the Commission for Air Quality Management. It has four stages that get stricter as pollution rises. Stage II is currently in force, restricting diesel generators and the burning of coal and firewood.

What causes Delhi’s winter smog?

Several factors combine: smoke from burning crop stubble in Punjab and Haryana, vehicle exhaust, road and construction dust, factory emissions and waste burning — all trapped close to the ground by cold, still winter weather. Fireworks during Diwali add to the problem.

What is the Delhi government’s Winter Action Plan?

A four-month plan running from 1 November to 28 February that restricts older, polluting vehicles from outside Delhi, denies fuel to vehicles without valid emission certificates, and bans dust-generating demolition and construction work.

How does Delhi’s air compare with safe levels?

The World Health Organization recommends that average PM2.5 levels over 24 hours should not exceed 15 micrograms per cubic metre. During Delhi’s pollution season, levels are often more than 25 times that limit.

Is stubble burning only an Indian problem?

No. Satellite data shows farm fires burning across the region, including in Pakistan’s Punjab, which recorded 13,241 agricultural fire detections between 1 and 29 October, compared with 3,158 in India’s Punjab. Smog is a shared regional problem.

Sources

• BBC News (via World Right Now), “Delhi’s toxic winter air is back — is the Indian capital prepared for pollution?”, 5 November 2026 — https://worldrightnowlive.com/story/delhi-s-toxic-winter-air-is-back-is-the-indian-capital-prepared-for-po
• Wirony, “Delhi’s air hits 350, worst in 287 days; 10 stations severe, GRAP Stage II on”, 4 November 2026 — https://www.wirony.com/india/general/delhis-air-hits-350-worst-in-287-days-10-stations-severe-grap-stage-ii-on-diwali-and-farm-fires-ahead/479-2026-11-04
• Jagran Josh, “Delhi-NCR air pollution: AQI turns hazardous at 451 in 4 days despite GRAP” — https://www.jagranjosh.com/general-knowledge/delhincr-air-pollution-aqi-turns-hazardous-at-451-in-4-days-despite-grap-why-is-it-worsening-before-diwali-how-pakistan-is-also-behind-this-1820013573-1
• The Mondo News, “Delhi air pollution worsens ahead of Diwali as air quality declines” — https://themondonews.com/science/delhi-air-pollution-worsens-ahead-of-diwali-as-air-quality-declines/
• Human Resources Online, “Air quality worsens in Delhi and parts of northern India ahead of Diwali weekend” — https://www.humanresourcesonline.net/air-quality-worsens-in-delhi-and-parts-of-northern-india-ahead-of-diwali-weekend

This article is for general information and education only. It is not legal or financial advice.