With the withdrawal of the monsoon, the air quality in Mumbai has started to deteriorate.
On Sunday, the air quality index (AQI) – the pollutant measuring indicator – for the city was 210 (poor category). The pollution levels are likely to become worse with the onset of winter, said officials from the System for Air Quality Weather Forecasting and Research (SAFAR), a government-appointed body that independently monitors air quality.
Between June and the first week of October, AQI levels in the city were below 100, as most air pollutants get washed away in heavy rain.
“The minor drop in minimum temperatures, especially in the morning, leaves pollutants trapped closer to the surface. This leads to a smog cover and deteriorates the air quality,” said Gufran Beig, project director, SAFAR.
AQI levels from 0-100 fall under the ‘good’ category, 101-200 ‘moderate’, 201-300 ‘poor’ and 301- above is ‘very poor’. While some locations in and around the city such as Mazgaon and Navi Mumbai recorded very poor AQI levels, poor levels were recorded at Andheri and Bandra-Kurla Complex.
The southwest monsoon withdrew from Mumbai on October 14 and dry weather has prevailed over the city for over a week.
Beig said during winter, pollutants get trapped closer to the ground owing to the process of inversion – low temperatures, drop in wind speed and high moisture.
Officials from the weather bureau said the day temperatures were below normal levels on Sunday, while the night temperatures were closer to the normal mark. Moisture levels were moderate, as the weather stations at Colaba and Santacruz recorded 81% and 71% humidity. A partly cloudy sky was predicted for Monday.