In Delhi, the Diwali readings for PM2.5 and PM10 rose respectively by roughly five and three times from the previous week’s readings, statistics tabled in Parliament by the Ministry of Environment, Forest and Climate Change show.
While the PM2.5 reading rose from 116 micrograms per cubic metre to 512 µg/cu.m on Diwali (October 27), PM10 rose from 190 to 600. Air quality on Diwali deteriorated significantly in Delhi, Lucknow, Agra, and Kolkata. While it deteriorated in Bengaluru too, the latter remained the least polluted among these cities as both PM2.5 and PM10 levels remained within prescribed limits.
The Central Pollution Control Board conducted air quality monitoring for seven cities — Delhi, Agra, Bengaluru, Bhopal, Kolkata, Lucknow, and Vadodara. It measured air quality for pre-Diwali, Diwali and post-Diwali periods. The Board prescribes the National Ambient Air Quality Standard (NAAQS) for PM2.5 (Particulate Matter 2.5) at 60 µg/cubic metre (24-hourly average), and PM10 (Particulate Matter 10) at 100 µg/cu.m.
On pre-Diwali days, PM10 and PM2.5 were already significantly above NAAQS levels in Agra, Delhi, Lucknow and Kolkata, while the levels in the other three cities were below or slightly above these standards. On Diwali, all cities except Bengaluru crossed PM2.5 NAAQS values. On post-Diwali days (seven days after October 27), the levels of both pollutants fell in all these cities except Agra.
The question was raised by Trinamool Congress MP Shanta Chhetri in Rajya Sabha. In his reply, Minister of State Babul Supriyo said it was evident that north Indian cities displayed similar dispersion patterns.
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