New Delhi, Nov 9 (PTI) Delhi recorded a marginal improvement in air quality the morning after Diwali, with its Air Quality Index (AQI) declining to 371 from 382, while noise levels on the festival day rose at 19 of the city's 26 monitoring locations compared to last year, according to a Delhi Pollution Control Committee report.
The report showed a 2.9 per cent fall in AQI at 10 am on Monday, the morning after Diwali, compared to other years, due to meteorological factors, and also cited higher wind speeds as the reason.
However, both the Diwali-day and post-Diwali readings were the highest for the corresponding mornings in the four-year comparison presented in the report.
Meanwhile, noise levels on Diwali ranged from 57.5 dB(A) at Najafgarh to 89.1 dB(A) at Karol Bagh, with 19 locations recording an increase in noise level as compared to 2025 and seven registering a decline, the report said.
Karol Bagh remained the noisiest of the monitored locations despite a marginal decline from 89.2 dB(A) last year.
Other locations recording relatively high levels included Jahangirpuri at 81.2 dB(A), Dwarka at 79.8 dB(A), Patparganj at 79.5 dB(A) and Vivek Vihar at 79.3 dB(A).
Sonia Vihar registered the largest rise in the reported decibel reading, from 64.3 dB(A) in 2025 to 74.9 dB(A) in 2026. Levels also increased at Jahangirpuri from 74 to 81.2 dB(A), Mundka from 62.5 to 68.2 dB(A), and Patparganj from 73.3 to 79.5 dB(A).
Ashok Vihar recorded the largest decline, from 74.9 dB(A) to 68.3 dB(A).
The other locations reporting lower readings were Rohini, Vivek Vihar, Connaught Place, Dr Karni Singh, Karol Bagh and Pusa, the report said.
Delhi's AQI fell by 11 points between 10 am on Diwali, November 8, and the same time on November 9, according to the report's principal comparison.
Morning wind speeds increased from 5-10 kmph to 10-15 kmph, it said.
"Overall Ambient Air Quality of Delhi showed minor improvement in terms of AQI due to meteorological factors," the committee said in its conclusion.
The overnight decline contrasted with increases recorded after Diwali in the previous three years. AQI rose from 210 to 301 in 2023, from 331 to 359 in 2024 and from 341 to 359 in 2025, according to the report.
Despite Monday's improvement, the post-Diwali reading of 371 exceeded the corresponding readings in all three preceding years.
Its hotspot chart also showed a mixed year-on-year picture, despite an accompanying statement that all 13 hotspots recorded increases. The plotted readings declined at Anand Vihar, Ashok Vihar and Wazirpur for 2026 post-Diwali readings as compared to 2025, while rising at the other 10 locations. Jahangirpuri recorded the highest Diwali-day AQI among the hotspots at 450.
The report's chart of 24-hour city-average particulate concentrations showed PM10 declining from 703 micrograms per cubic metre in 2025 to 682 in 2026, and PM2.5 falling from 520 to 473 micrograms per cubic metre.
The PM10 figures imply a decline of about 3 per cent, although the report's accompanying text and observations described it as a 30 per cent reduction.
The PM2.5 figures were consistent with the stated decline of about 9 per cent.
The committee said 13 monitoring locations recorded lower PM10 concentrations and 14 recorded lower PM2.5 concentrations compared to last Diwali. It also reported that the six monitored gaseous pollutants - ammonia, sulphur dioxide, nitrogen dioxide, carbon monoxide, ozone and benzene - were within prescribed national standards.
The report recorded 1,248 crop-residue burning events across Punjab, Haryana, Uttar Pradesh and Delhi on Diwali, compared to 135 on the festival day last year, an increase of about 824 per cent.
Punjab accounted for 1,152 events, followed by Haryana with 80 and Uttar Pradesh with 16. Delhi recorded none. Punjab's count rose from 45 last Diwali, an increase of 2,460 per cent, according to the report.
The festival-day comparison covered different calendar dates as per the dates of Diwali: from October 20 in 2025 to November 8 in 2026.
(This story has not been edited by THE WEEK and is auto-generated from PTI)