NEW DELHI: Delhi’s air pollution levels deteriorated sharply ahead of Diwali, with the city recording its worst pre-Diwali pollution spike since 2019, according to an analysis by the Centre for Research on Energy and Clean Air (CREA). The national capital was also the only megacity among five assessed to record a monthly average PM2.5 concentration exceeding the daily National Ambient Air Quality Standards (NAAQS) in October.
CREA’s pre-Diwali air quality analysis found that PM2.5 concentrations began rising steeply on November 5, reaching 227 micrograms per cubic metre (µg/m³). By 6 am on Friday, hourly concentrations had climbed to 300 µg/m³, five times the prescribed 24-hour national standard. The levels deteriorated further to 309 µg/m³ and then 323 µg/m³ in the early hours before showing a marginal improvement.
The analysis found that Delhi recorded a monthly average PM2.5 concentration of 69 µg/m³ in October, significantly higher than the daily NAAQS limit of 60 µg/m³. Mumbai followed with 46 µg/m³, Kolkata recorded 45 µg/m³, while Chennai and Bengaluru reported 29 µg/m³ each.
Delhi also recorded 21 days in October when daily average PM2.5 concentrations exceeded the national standard. Mumbai and Kolkata recorded three and four such days, respectively, while Chennai and Bengaluru remained below the prescribed limit throughout the month.
Stubble burning has also contributed to the worsening pollution, with its share in Delhi’s PM2.5 levels increasing during the onset of the peak burning season.
Manoj Kumar, analyst at CREA, said, “Stubble burning contributed up to 5.3% to Delhi's PM2.5 concentrations in October 2026. With the onset of the peak stubble-burning period in November, the practiceʼs contribution increased, reaching 16% on 4 November. For comparison, the contribution peaked at around 22% in November 2025 and 38% in 2024. The contribution from stubble burning is expected to decline sharply after the second week of November as the burning activity subsides.”
Meanwhile, Delhi’s Air Quality Index (AQI) has remained in the ‘very poor’ category for four consecutive days, according to Central Pollution Control Board (CPCB) data.
The AQI stood at 369 on Thursday, marginally better than Wednesday’s 377. On Tuesday, it was recorded at 350, reflecting a sustained deterioration in the capital’s air quality ahead of Diwali.
However on Friday, the situation worsened and the average AQI crossed 400 mark at over 35 stations out of 59 stations as per CPCB.
Manoj Kumar, analyst at CREA, said, “Stubble burning contributed up to 5.3% to Delhi's PM2.5 concentrations in October 2026. With the onset of the peak stubble-burning period in November, the practiceʼs contribution increased, reaching 16% on 4 November. For comparison, the contribution peaked at around 22% in November 2025 and 38% in 2024. The contribution from stubble burning is expected to decline sharply after the second week of November as the burning activity subsides.”
Meanwhile, Delhi’s Air Quality Index (AQI) has remained in the ‘very poor’ category for four consecutive days, according to Central Pollution Control Board (CPCB) data.
The AQI stood at 369 on Thursday, marginally better than Wednesday’s 377. On Tuesday, it was recorded at 350, reflecting a sustained deterioration in the capital’s air quality ahead of Diwali.
However on Friday, the situation worsened and the average AQI crossed 400 mark at over 35 stations out of 59 stations as per CPCB.
