Diwali night fireworks send PM2.5 levels skyrocketing in Delhi-NCR

AQI slips into 'very poor' category, early respite not expected

Delhi and its adjoining areas recorded one of the worst air pollution days on Tuesday, with particulate matter 2.5 (PM2.5) levels surging across North India, largely due to a spike in firecracker use the previous night.

 

The city’s Air Quality Index (AQI) averaged 351 at 4 pm on Tuesday, while readings exceeded 300 across neighbouring cities including Ghaziabad, Gurugram and Noida, placing the entire Delhi-NCR region in the “very poor” category. The figures reflect 24-hour averages.

 

In some parts of Delhi, including Bawana, AQI levels crossed 400.

 

By comparison, Mumbai recorded an average AQI of 271, categorised as “poor”, while Kolkata’s average of 174 fell into the “moderate” range. Some Kolkata localities, however, slipped into the “poor” category due to firecracker emissions.

 

 

In North India, the outlook for the next few days is grim too. The Ministry of Earth Sciences said in a statement: “For the period between October 22 and October 24, the air quality of Delhi is very likely to be in the “very poor” category.”

 

A small relief is that incidents of stubble burning, which had sharply declined in early October due to persistent rains, were not the primary driver of this spike in pollution. Yet concern remains, as the peak harvest season is yet to arrive. Data from the Punjab Pollution Control Board (PPCB) shows a more than threefold increase in farm fire incidents over the past 10 days, with 116 cases reported by October 11.

 

Meanwhile, an analysis of Central Pollution Control Board (CPCB) data by the research and advisory group Climate Trends indicated that Delhi’s average PM2.5 concentration reached 488 micrograms per cubic metre in the 24 hours following Diwali, more than three times the pre-festival level of 156.6 micrograms per cubic metre.

 

The analysis, covering 2021 to 2025, showed a consistent post-Diwali spike in PM2.5 levels, with 2025 marking the most polluted post-festival period since 2021. Previous years saw average PM2.5 rises from 163.1 to 454.5 in 2021, 129.3 to 168 in 2022, 92.9 to 319.7 in 2023, and 204 to 220 in 2024.

 

The study attributed the surge primarily to local emissions from firecrackers, coupled with stagnant winds of less than one metre per second and temperature inversions that trap pollutants near the surface.

 

Delhi's environment minister  Manjinder Singh Sirsa however said that Delhi's AQI this year was better than last year when there was ban on all types of crackers. 

 

“The high PM2.5 concentration is due to local firecracker emissions across different parts of Delhi. Wind speeds were extremely low, leaving no scope for dispersion,” said S K Dhaka, professor at Rajdhani College, University of Delhi. He added that even so-called “green” firecrackers contributed significantly to particulate accumulation and stressed the need to regulate their quality and composition.

 

Despite court bans on firecrackers and repeated advisories, the capital’s air quality has consistently fallen into the “severe” category (AQI above 400) after Diwali for most of the past decade.

 

Doctors warn that breathing Delhi’s air during such episodes is equivalent to smoking about 10 cigarettes a day. Prolonged exposure can trigger or worsen asthma, bronchitis and chronic obstructive pulmonary disease, and significantly raise the risk of heart disease.

 

In a related development,  Sirsa also accused the Aam Aadmi Party (AAP) government of Punjab on Tuesday of compelling farmers to burn crop residue to elevate pollution levels in the national capital. He displayed videos, purportedly showing stubble burning in Punjab, at a press conference. Delhi Home Minister Ashish Sood said those who burst firecrackers beyond 10 pm on Diwali night behaved “irresponsibly”.

 

Police have registered over 100 cases across Delhi for alleged violations of Supreme Court guidelines on firecracker use, and more than 50 cases for illegal sales during Diwali, officials said.