A day after the city recorded Air Quality Index (AQI) of 149, Tuesday saw Mumbai’s air quality improving drastically, as at 7 pm, the System of Air Quality and Weather Forecast and Research (SAFAR) recorded an AQI of 41, which falls in the good category.
The experts attributed the improvement in AQI to the change in wind speed direction. Mumbai on Tuesday also recorded a minimum temperature of 17 degrees Celsius, which is three degrees less than normal.
“Owing to the change in wind speed, the AQI has improved. Mumbai is experiencing inland winds, which has also resulted in the decline in minimum temperature. Humidity is also low and the sky is clear. Therefore, this is a favourable condition for having better AQI,” said Mahesh Palawat, meteorologist and climate expert from Skymet Weather.
The SAFAR app showed pockets of Mumbai, which had been recording poor AQI for the last one-and-a-half months, recording good AQI. Mazgaon showed an AQI of 45, followed by Worli (87) and Malad (98). These three areas had recorded an AQI between 120-250 throughout the last one week.
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However, Colaba continued to record moderate AQI with 166, followed by Chembur (239). “The AQI is varying in certain pockets mainly due to wind direction and emission level. Areas that have high emission rate but slow wind speed are seeing poor air quality while those with high wind speed are seeing an improved AQI,” said Bhagwan Kesbhat, founder of environment NGO Watavaaran.
Between October and November 28, the city’s AQI had oscillated between the poor and moderate categories.
Weather experts said that after monsoon withdrawal in mid-October, air speed became slow in Mumbai, leading to the suspended particulate matter staying in the lower atmosphere for a long time.