Delhi’s Diwali turns dark: Air quality hits four-year low despite cleaner fields

By: Team India Tracker

Delhi’s Diwali-day AQI hit its highest since 2021 at 345, compared with 330 in 2024, 218 in 2023, 312 in 2022, and 382 in 2021—despite a 77% drop in stubble burning this year

Air pollution in the national capital region (NCR) spiked to its worst level in four years this Diwali, as firecrackers lit through the night wiped out the gains made from a sharp drop in farm fires. According to the Central Pollution Control Board (CPCB), Delhi’s 24-hour average Air Quality Index (AQI) on Diwali day, October 20, stood at 345, placing it firmly in the “very poor” category. By October 21, the morning after the festivities, the number had climbed to 351—a toxic mix of smoke, chemical odour, and poor visibility hanging over the city.

For comparison, the Diwali-day AQI was 330 in 2024, 218 in 2023, 312 in 2022, and 382 in 2021. That makes Diwali 2025 the city’s most polluted since 2021—and worse than last year, even though stubble burning, one of northern India’s biggest seasonal polluters, fell by more than 77 per cent this year.

The real story lies in the PM2.5—tiny particles that penetrate deep into the lungs and bloodstream. On October 20 night, Delhi’s PM2.5 concentration peaked at 675 micrograms per cubic metre, nearly 100 times higher than the World Health Organisation’s safe limit of 5. The city’s average PM2.5 over 24 hours was 488 micrograms, marking a 212 per cent jump from pre-Diwali levels. The CPCB called the increase “severe and unprecedented” for the season.

Green crackers, same old smoke

The Supreme Court this year allowed “green crackers”— supposedly less polluting versions of traditional fireworks—to be used for a limited period during Diwali. But few residents seemed to follow those rules.

The sound of fireworks had drowned out any hope of cleaner celebrations. From Connaught Place to the suburbs of Noida and Gurugram, firecrackers burst well past the allowed hours. “The Supreme Court has prioritised the right to burn crackers over the right to live and breathe,” said Amitabh Kant, former CEO of NITI Aayog and India’s G20 Sherpa in 2023, in a post on X.

The apex court’s orders are rarely enforced on the ground. In previous years, the Delhi government imposed complete bans on firecrackers, but with limited success. The return of legal “green crackers” this year appears to have had the same result: a festival night of toxic air, followed by a morning of regret.

Cleaner fields, dirtier skies

Ironically, this Diwali coincided with one of the cleanest stubble-burning seasons in years. Data from the Indian Agricultural Research Institute show that farm fires in Punjab and Haryana—a major source of smoke drifting into Delhi every winter—fell by 77.5 per cent compared with last year.

That means the air this time wasn’t poisoned by farmers clearing their fields, but by residents lighting up the night. “When you remove agricultural burning from the equation and still see AQI worsening, the source becomes obvious—firecrackers,” said an official at the CPCB.

Delhi’s geography compounds the problem. With winter setting in, cooler air traps pollutants closer to the ground. Add to that the city’s already heavy traffic and construction dust, and Diwali becomes a perfect storm for poor air quality.

Metros choke too

The pollution wasn’t limited to Delhi. Across India’s major cities, air quality deteriorated after Diwali. Mumbai and Chennai reported worse post-Diwali AQI numbers this year than in 2024. Kolkata and Bengaluru, however, saw relatively cleaner skies.

In Delhi alone, 36 of the city’s 38 air-monitoring stations recorded AQI readings in the “very poor” to “severe” range. Visibility dropped sharply, and residents complained of breathing discomfort. Schools and offices advised people to limit outdoor activity.

Despite years of campaigns, Delhi’s Diwali pollution remains a stubborn problem. The CPCB’s four-year data show a consistent spike in air pollution around the festival week, suggesting that the city’s celebrations are inseparable from their smoky aftermath.

Experts say the issue goes beyond individual choices. Cleaner festivals require collective discipline, but they also need affordable, accessible alternatives for celebration. Right now, pollution is a shared problem, but responsibility isn’t shared equally, they mentioned.

For millions in the capital, the festival of lights has once again become a season of smog. The celebrations may have brought joy and colour, but as Delhi’s air turned acrid, one truth lingered in the haze—the tradition of fireworks still burns brighter than the desire to breathe clean air.