New Delhi air hits 879 µg/m³ PM2.5 after Diwali fireworks, nearly 59 times WHO limit

Peak readings early on Monday

Air quality in New Delhi reached severe levels early on Monday, 9 November, after the Diwali festival. IQAir, citing data from a city government monitoring station in the Mandir Marg area of central Delhi, recorded 879 micrograms of PM2.5 per cubic meter. That figure is nearly 59 times the 15 microgram limit set by the World Health Organization as a daily average. Several parts of the capital posted an Air Quality Index above 350, which falls in the severe category. The reading followed a night of fireworks, with the skies lit up on Sunday night and now covered by a thick layer of toxic smog. Visibility fell as a grey haze settled over streets and high-rise buildings.

Fireworks despite the court's limits

In October, India's Supreme Court restricted conventional firecrackers and allowed only 'green firecrackers' in three-hour windows on Saturday, 7 November and Sunday, 8 November. Many residents ignored the curbs and set off firecrackers on Sunday evening, releasing smoke and fine particles into the air. Delhi recorded its worst Diwali-eve air in a decade on Saturday, 7 November. Green crackers produce fewer emissions but still release particulate matter and other pollutants. Vehicles fitted with mist-spraying cannons were deployed in the capital to knock down suspended dust. The haze also reached Agra, Noida and Mumbai, where the India Gate and the Taj Mahal were barely visible and residents and tourists reported breathing difficulties.

Why the air stays so bad

Winter smog in the capital is fed by several sources. According to the Environment Ministry, vehicle traffic accounts for 23% of winter pollution in Delhi, crop-residue fires for 20% and industry for 9%. The largest single share, 27%, comes from secondary particles that form when emissions from vehicles, industry and burning mix in the atmosphere. After the rice harvest, farmers in the neighbouring states of Punjab and Haryana burn leftover stalks, and the smoke drifts toward New Delhi. From November to January, falling temperatures, low wind speeds and stagnant air keep pollutants close to the ground. Construction dust and other local sources add to the load throughout the season.

Vehicle traffic23%

Crop-residue fires20%

Industry9%

Secondary particles formed in the atmosphere27%

Vehicle traffic

23 %

Crop-residue fires

20 %

Industry

9 %

Secondary particles formed in the atmosphere

27 %

Data from the article text

Health cost

Fine particles smaller than 2.5 micrometers can travel deep into the lungs and from there into the bloodstream. They can trigger heart, circulatory and respiratory disease, including asthma and lung cancer. A 2024 study published in The Lancet estimated that 3.8 million deaths in India between 2009 and 2019 were linked to air pollution. The Delhi metropolitan area, home to more than 30 million people, regularly ranks among the most polluted urban areas in the world during winter. The 879 reading stood far above the daily guideline on Monday.

Mandir Marg, early Monday 9 November879

WHO 24-hour guideline15

Mandir Marg, early Monday 9 November

879 µg/m³

WHO 24-hour guideline

15 µg/m³

Data from the article text

Limits and what officials are doing

Authorities have imposed limits on construction activity and restrictions on diesel generators, and courts have sought curbs on firecrackers. Le Temps reports that the municipality's efforts to limit pollution peaks and restrict firecracker use have so far had little effect. Each year, the measures have not prevented the return of severe pollution. Environmentalists say long-term solutions, such as cleaner energy, are needed. The haze can linger over the capital and surrounding areas for days, so residents may keep breathing polluted air well after the festival ends.