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Particulate matter (PM) concentrations soared on Diwali night in Delhi with fireworks being set off in contravention of the ban that is in place.
At some monitoring stations on Diwali night, the PM 2.5 level reached a figure that was as much as 15 times and PM 10 around 10 times the 24-hour standard, according to data from the Delhi Pollution Control Committee (DPCC).
At Nehru Nagar in South Delhi, the PM 2.5 concentration hit 943 µg/m3 at midnight, up from 75 µg/m3 at 6 pm on Monday. The 24-hour standard for PM 2.5 according to the National Ambient Air Quality Standards is 60 µg/m3. The PM 10 concentration at the Nehru Nagar station also saw a spike around midnight, hitting 1086 µg/m3, which is a little more than 10 times the 24-hour standard of 100 µg/m3 for PM 10. In contrast, over the preceding 24 hours, the PM 2.5 level peaked at 324 µg/m3 at 7 pm on Sunday at Nehru Nagar.
At the Jawaharlal Nehru Stadium, there was a similar rise in particulate matter concentrations around midnight when PM 2.5 levels climbed up to 738 µg/m3 from 66 µg/m3 at 6 pm. The particulate matter level had fallen to 146 µg/m3 by 8 am on Tuesday. At Ashok Vihar as well, the PM 10 concentration breached the 1,000 mark to hit 1029 µg/m3 at midnight. The PM 2.5 level at Ashok Vihar at the same time was 830 µg/m3.
At most stations, the particulate matter levels had fallen by Tuesday morning. At Nehru Nagar for instance, the PM 10 concentration was down to 216 µg/m3 at 8 am and at Ashok Vihar, PM 2.5 levels had fallen to 163 µg/m3 at the same time.
While calm conditions make it difficult for pollutants to disperse, the wind speed had picked up marginally at these stations on Tuesday morning. At Ashok Vihar, a wind speed of 0.5 m/s at midnight increased to 1.5 m/s by 8 am.
The 24-hour average air quality index (AQI) continues to remain in the ‘very poor’ or ‘poor’ categories at all monitoring stations in the city. Delhi recorded the season’s first ‘very poor’ air day on Monday, with an AQI of 312.
At Anand Vihar, the 24-hour average AQI at 8 am on Tuesday was 356, while it was 371 at Nehru Nagar and 329 at Ashok Vihar.
According to a forecast issued by the Air Quality Early Warning System on Monday, the AQI is set to remain in the ‘very poor’ category on Tuesday.
The Delhi government had imposed a ban on the manufacture, sale, storage and bursting of firecrackers.
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