Delhi’s Air Quality Index (AQI) plunged to its worst post-Diwali level in five years on Tuesday morning following Diwali celebrations.
According to an analysis by Climate Trends, an environment and climate change research organization, the average PM 2.5 after Diwali was recorded at 488 µg/m³, a 212% increase from pre-Diwali levels.
Even on Wednesday, the national capital recorded an air quality index (AQI) of 345, which the Central Pollution Control Board (CPCB) said was in the “very poor category”.
This is despite a 77 percent drop in stubble burning incidents this October due to unprecedented floods in Punjab and Haryana, the report said. The findings suggest that while curbing farm fires alone is not enough to clean up Delhi’s toxic air, firecracker emissions remain the dominant cause of the short-term collapse in Delhi’s air quality during the festive season.
AAP-BJP political blame game
The report comes amid a political pollution blame game in the state capital, with Delhi Environment Minister Manjinder Singh Sirsa accusing the Aam Aadmi Party (AAP) of forcing Punjabi farmers to burn crops and stubble ahead of Diwali.
Aam Aadmi Party president and former Delhi minister Saurabh Bharadwaj launched a scathing attack on the government on Tuesday, accusing it of failing to control pollution after Diwali celebrations and questioning why promised “artificial rain” was not used to improve air quality.
At a press conference on Tuesday, Sirsa showed videos of alleged farmers burning stubble in regions like Tarn Taran and Bathinda.
“The Aam Aadmi Party, which has been running an incompetent government in Delhi for the past 10 years, has been involved in questionable activities for the last four days… These visuals are from Tarna Taran and Bathinda, notice how people’s faces are covered. Farmers are forced to burn stubble while hiding their identity,” Sirsa said.
The minister also cited 2020 data to argue that firecrackers were not responsible for Delhi’s AQI today, which dipped into the “severe” category in key areas.
However, an analysis of Climate Trends of Central Pollution Control Board (CPCB) data from 2021 to 2025 shows that air pollution levels in Delhi jumped to dangerous highs during Diwali 2025, with post-Diwali PM 2.5 concentrations averaging 488 µg/m³.
An analysis of Climate Trends of Central Pollution Control Board (CPCB) data from 2021 to 2025 shows that air pollution levels in Delhi jumped to dangerous highs during Diwali 2025, with post-Diwali PM 2.5 concentrations averaging 488 µg/m³.
Over a five-year analysis, the data shows a consistent rise in Diwali-related pollution, with PM 2.5 readings typically doubling or tripling during the festival night and persisting into the next day.
Firecracker emissions remain the dominant cause of the short-term collapse in Delhi’s air quality during the festive season, the report said.
“This year’s Diwali has turned out to be even worse than before, with the data clearly showing a sharp rise in pollution levels, with post-Diwali PM readings averaging around 488 compared to just 156.6 before the festival. This is more than a three-fold increase, making 2025 one of the most polluted Diwalis in recent years. The increase between 2nd and 2nd night directly corresponds to firecrackers across Delhi-NCR, Palak Balyan, Head of Research, Climate Trends, said.
Are green cookies sustainable?
The sharp drop in Delhi’s AQI comes as the Supreme Court allowed the bursting of ‘green’ crackers for two hours this year. However, the residents defied the SC order and continued to burst crackers even beyond the reserved slot.
A week before Diwali, the Supreme Court allowed the sale and cracking of green crackers in the Delhi-National Capital Region (NCR) between October 18 and 21 for Diwali.
Chief Justice of India (CJI) BR Gavai directed the Central Pollution Control Board (CPCB) and State PCBs to monitor the Air Quality Index (AQI) from October 18 and submit a report to the court.
Balyan said visual and ground data confirmed that burning the so-called “green” biscuits made no measurable difference compared to regular ones. “It is now evident that allowing firecrackers at this time of the year is simply not sustainable for the already critical air quality of the NCR region.”
How did stubble burning affect pollution?
An earlier comparative analysis of satellite fire data, Central Pollution Control Board (CPCB) data and Climate Trends found that Punjab and Haryana combined saw only 175 stubble burning incidents between October 1 and 12 this year, down from 779 during the same period last year.
This about 77.5% decline was mainly due to waterlogging caused by floods, which delayed the harvest of rice fields and prevented farmers from burning crop residues, the report said.
What do the experts say?
Experts analyzing the Climate Trends report said that it is most likely that the high concentration of PM 2.5 is due to the local emission of firecrackers in different parts of the city during this auspicious festival night of Diwali.
An earlier comparative analysis of satellite fire data, Central Pollution Control Board (CPCB) data and Climate Trends found that Punjab and Haryana combined saw only 175 stubble burning incidents between October 1 and 12 this year, down from 779 during the same period last year.
“The wind speed is quite low, less than 1 m/s, with a northwest-northwest direction, so there is no chance to carry pollutants from one place to another in the short span of a few hours of firecrackers burning. As for the relative humidity at various DPCC stations, the range remains from 60 to 90; in the rural agricultural belt on the west side of the city, it is reduced to 80%, and around 80% it is 10%.” said Dr SK Dhaka, Professor, Rajdhani College, University of Delhi.
“We concluded that green firecrackers increase particulate matter at a rapid rate; and the pollution is local in nature, not transported from other places. This suggests that we need to check the quality of green firecrackers,” said Dr. Dhaka.
What are the main findings of the report?
-Diwali 2025 saw the post-Diwali PM 2.5 average at 488 µg/m³, a 212% increase from pre-Diwali levels.
-The maximum concentration reached 675 µg/m³ late at night on October 20, 2025.
– Wind speeds below 1 m/s prevented the dispersion of pollutants.
-The drop in temperature after Diwali (from ~27°C to ~19°C) created inversion conditions and trapped pollutants.
• In all years, PM2.5 readings spike during Diwali and peak either late at night or early morning after the festival.
• The year 2025 shows the highest recorded mean (488 μg/m3) and maximum concentration (675.1 μg/m3 after Diwali), indicating heavy pollution build-up.
This year’s Diwali turned out to be even worse than before; the data clearly shows a sharp rise in pollution levels.
• 2022 and 2023 show relatively lower averages, with 2023 having the lowest pre-Diwali average (92.9 μg/m3).
• 2025 Post-Diwali (488) is the highest in all years, showing an alarming upward trend in post-festival pollution.
