India, Nov. 21 -- In light of rising air pollution with the advent of winter, Mumbai's civic body has sounded a warning for construction sites and industries: if the air quality index (AQI) of a ward stays consistently above AQI 200 ("Poor") for three days or more, all construction and industrial activity will be stopped under the Graded Response Action Plan (GRAP 4). Flying squads have been constituted to enforce these regulations.

Since November 13, for the past seven days, the 24-hour AQI of Deonar has consistently been over 200, with spikes taking the hourly AQI even higher. On Thursday, too, the 24-hour AQI was 271.

Mazgaon, another locality consistently in the "poor" category, has had its AQI over 200 since November 16, for five d...