If Mumbaikars are finding the air more difficult to breathe this week, blame it on the spirited Diwali celebrations the city had witnessed. Several areas in the city saw a steep rise in suspended particulate matter (SPM), respirable suspended particulate matter (RSPM), nitrogen oxides (NOx) and sulphur-dioxide (SO2), indicates an ambient air quality reading done by the Maharashtra Pollution Control Board (MPCB) between October 17-19.

MPCB has air quality monitoring stations in Mahul, Chembur, Sion, Mulund, Bandra, Parel, Kalbadevi and Worli. Its hour-to-hour monitoring during the nights of Diwali reveals that affluent suburbs like Bandra saw SPM levels crossing 1,000 micrograms per cubic metre (ug/m3) of air several times. On October 17, at 11 pm, SPM levels there peaked at 1,778.8 ug/m3 while RSPM rose to 951.9 ug/m3; the average on these days were twice the permissible limits at 414.2 ug/m3 SPM and 190.4 ug/m3 RSPM.  

On October 18 and the next day, SPM averaged here at a high 377 and 328 ug/m3 respectively. NOx level remained much higher than the permissible 80 ug/m3 limit, at 249 ug/m3 on October 16 and 181, 176 and 155 ug/m3 between October 17-19.

In Mulund, average RSPM levels rose considerably, reaching 197 ug/m3 on October 18. This was in sharp contrast to last Diwali, which had shown RSPM levels in the western suburbs (Bandra) and eastern suburbs (Mulund) only minimally exceeding the normal of 100 ug/m3.

B D Wadde, regional officer, Mumbai, at MPCB, said, “Besides bursting of crackers, the weather plays an important role in carrying the smog upwards and clearing ground-level atmosphere. This year, the weather was not too sunny during Diwali. As a result, the smoke stayed at the lower levels for a longer period.”

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