A four degrees Celsius drop in temperature between Saturday night and Sunday morning pushed up pollution levels in the city.
The Santacruz weather station, representative of Mumbai, recorded 16.4 degrees Celsius, 4.5 degrees Celsius below normal at 5.30am on Sunday as compared to 20 degrees Celsius, 0.9 degree Celsius below normal on Saturday.The night temperature at Colaba, too, was a degree Celsius below normal at 22 degrees Celsius.
The night temperature of 16.4 degrees Celsius was also recorded on November 11, which is the lowest November night temperature since 2012.
Researchers said this led to pollutants being trapped closer to the earth’s surface with the air quality index (AQI) — pollutant measuring indicator — at 225 during the day and 222 by the evening — both falling under the ‘poor’ category.
The System of Air Quality Weather Forecasting and Research (SAFAR) predicted the AQI for Monday will be 223 (poor).
Officials from the weather bureau attributed the drop in temperatures to a change in wind pattern. “Winds over the city late Saturday night and early Sunday morning were north-westerly [cool winds] that led to a cooling effect,” said KS Hosalikar, deputy director general, western region, India Meteorological Department (IMD), adding that it is expected to continue until Tuesday. “During the day, the winds are not strong and this phenomenon has led to pollutants remaining suspended closer to the surface. A thin layer of smoke was visible on Sunday evening.”
On Sunday, Malad and Navi Mumbai were the most polluted spots in the city, recording ‘very poor’ AQI levels. While the remaining locations recorded either ‘poor’ or ‘moderate’ air quality, Borivli had the cleanest air for the third day in a row with an AQI of 100, falling under the ‘good’ category.
Day temperatures were 2 degrees Celsius above normal, similar to previous days. While Colaba recorded 35.5 degrees Celsius, 2.4 degree Celsius above normal, 34.8 degrees Celsius was recorded at Santacruz, which was 1.5 degree Celsius above normal. The weather bureau predicted a clear sky for Monday morning.
Mumbai (overall) on Sunday morning: 225 (Poor)
Mumbai (overall) on Sunday evening: 222 (Poor)
Mumbai (overall) forecast for Monday: 223 (Poor)
Delhi (overall) on Sunday: 347 (Very Poor)
|Location||AQI on Sunday||AQI forecast for Monday|
|Malad||315 (Very Poor)||313 (Very Poor)|
|Navi Mumbai||302 (Very Poor)||302 (Very Poor)|
|Bandra Kurla Complex||268 (Poor)||269 (Poor)|
|Andheri||256 (Poor)||256 (Poor)|
|Mazgaon||220 (Poor)||215 (Poor)|
|Chembur||213 (Poor)||218 (Poor)|
|Bhandup||185 (Moderate)||197 (Moderate)|
|Colaba||182 (Moderate)||180 (Moderate)|
|Worli||178 (Moderate)||197 (Moderate)|
|Borivali||100 (Good)||97 (Good)|
(All AQI levels are in PM2.5 values monitored by the SAFAR)