Air pollution in parts of Delhi shot up to more than 50 times the World Health Organisation's safe limit on Deepavali night, as residents burst firecrackers well past the deadline set by the Supreme Court, official data showed on Monday, November 9, 2026.
The level of PM2.5, one of the most harmful pollutants, reached 760.99 micrograms per cubic metre at Akshardham at 11 pm on Sunday, November 8, according to data from the Delhi Pollution Control Committee. That figure is about 50.73 times the World Health Organisation's permissible limit of 15 micrograms per cubic metre for a 24-hour period.
At Anand Vihar, another monitoring station in the capital, PM2.5 levels reached 767 micrograms per cubic metre at the same hour, about 51.13 times the global health body's guideline. At Jawaharlal Nehru Stadium, the reading was 702 micrograms per cubic metre, about 46.8 times the limit.
The spike came as Delhiites burst firecrackers far beyond the 10 pm deadline prescribed by the Supreme Court for Deepavali night, despite repeated appeals from the authorities to comply with the rules.
By Monday morning, the air quality across the national capital had deteriorated sharply. The Air Quality Index slipped into the severe category in parts of the city in the early hours, according to data shared by the Central Pollution Control Board.
The air quality station at ITO recorded an alarming Air Quality Index of 406 at around 4.20 am, placing it in the severe band. The city's overall index stood at 368 at 7 am, in the very poor category, with PM2.5 emerging as the prominent pollutant, according to the pollution control board's real-time data.
Fifteen locations across the capital recorded severe air quality on Monday morning. By 8 am, 24 of the 54 monitoring stations then reporting data had readings above 400, the threshold at which Indian authorities classify air as severe. India Today, citing the pollution board, put the city's overall index at 384 at 9 am.
Under the Central Pollution Control Board's National Air Quality Index classification, readings between 301 and 400 are categorised as very poor, while readings between 401 and 500 fall in the severe category. A reading above 400 is considered a serious health risk, particularly for children, the elderly and people with respiratory conditions.
The Supreme Court's Rules and the Ban
The Supreme Court had permitted the use of certified green firecrackers for Deepavali, but only within strict time windows. In an order dated October 29 and made public on November 2, a bench of Justices M. M. Sundresh and Prasanna B. Varale permitted the manufacture, sale and bursting of approved firecrackers between 6 am and 7 am and between 8 pm and 10 pm on November 7 and 8.
The court had described Deepavali fireworks as a religious practice, and allowed green crackers for two days in Delhi and the National Capital Region. At the same time, it directed that the complete ban on firecrackers be restored from November 9.
The Delhi government, ahead of the festival, had appealed to people to comply with the Supreme Court's directions on the sale and use of green firecrackers. However, reports from several neighbourhoods indicated that firecrackers continued to be burst well beyond the permitted hours, despite the restrictions.
Stage III of the Graded Response Action Plan, the emergency framework for tackling severe pollution in Delhi and the National Capital Region, is already in force. The Commission for Air Quality Management invoked Stage III on November 6, after pollution levels deteriorated into the severe category.
Stage III is the second-most severe tier of the plan, and Stage I curbs also remain in force alongside it. Stage IV applies when the Air Quality Index goes above 450. The Air Quality Early Warning System for Delhi has forecast that air quality could slip into the severe category from November 9 and remain there over the subsequent few days.
The comparison between the hourly PM2.5 readings and the World Health Organisation's 24-hour guideline has drawn some caution from experts. Business Standard noted that the hourly concentration was being compared against a 24-hour guideline, rather than a like-for-like average. Even so, the readings underline the scale of the pollution spike on Deepavali night.
What Contributed to the Pollution
Firecracker smoke was not the only source of pollution in the capital. Delhi's own Decision Support System estimated that transport accounted for 19 per cent of the city's pollution load for the day, while stubble burning contributed about 3.5 per cent, falling to about 2.99 per cent on Monday. A separate projection, reported by India Today citing the Press Trust of India, put the stubble-burning share for Sunday at 5.4 per cent.
The capital had already been breathing poor air before the festival. A thick layer of smog had hung over the city in the days leading up to Deepavali, and forecasters had warned that the festival would make matters worse. Two independent models had projected severe air from Saturday through Monday, with one forecast saying that PM2.5 could reach 45 times the World Health Organisation's safe limit.
The experience of previous years offers a grim comparison. Delhi's overall Air Quality Index after Deepavali was 351 in 2025, in the very poor category. In 2021, the post-Diwali index reached 454 amid widespread violations of the cracker ban. One report described the 2026 Deepavali eve as the most toxic in ten years.
The Health Toll
The festival also took a direct toll on health. In Tamil Nadu, one child succumbed to burn injuries, and 269 people were treated for firecracker-related burns across the state during the Deepavali festivities, according to official data tracking emergencies over a 24-hour window.
In Delhi, hospitals traditionally report a surge in patients with breathing difficulties, eye irritation and burn injuries in the days after Deepavali. Doctors advise people with asthma and other respiratory conditions to stay indoors when pollution levels are severe, and to wear masks if they must go out.
The World Health Organisation recommends that 24-hour average PM2.5 levels should not exceed 15 micrograms per cubic metre. In Delhi during the pollution season, levels are often more than 25 times that figure, according to the BBC.
The Supreme Court's order also sets out what happens next. The court said it was short of adequate data to decide whether a complete ban would be the best solution, and directed that measurements be taken before it decides on further action. The complete ban on firecrackers, as imposed earlier, was restored with effect from November 9.
For residents of the capital, the immediate outlook is bleak. Forecasters have warned that air quality could remain in the severe category for several days, as calm winds and falling temperatures trap pollutants close to the ground.
The annual pattern is now familiar: a festival celebrated with fire and light, followed by days of smog that leave the city gasping. The question, as it is every year, is whether the rules will be enforced more strictly next time, and whether the city's air can be protected before the next Deepavali arrives.
(Reporting based on The Hindu and Business Standard.)