Heavy rain on Tuesday night, made Mumbai’s air quality (16) one of the best in the world on Wednesday, with its air cleaner than major international cities such as New York, Tokyo, Sydney, Singapore. It was also the second cleanest air day since June 2015.

The cleanest air day over the past four years was recorded on June 25, 2018, when AQI levels dropped to an all-time low of 13 (good).

Prior to Wednesday, the second lowest AQI since monitoring began was 18 (good) on June 6, 2018.

On June 28, an AQI of 22 (good) was recorded, while Tuesday witnessed clean air with an AQI of 21.

An AQI of 17 (good) has been predicted for Thursday. Navi Mumbai recorded the cleanest air in the Mumbai Metropolitan Region (MMR) with an AQI of 4 (good), which is expected to continue on Thursday.

SAFAR categorises AQI levels for PM2.5 in the 0-50 range as good; 51-100 as satisfactory; 101-200 as moderate; 201-300 as poor; 301-400 as very poor and above 400 as severe.

“With wind speed ranging at a maximum of 30kmph in Mumbai combined with high moisture levels, pollutants can’t settle close to the surface. Isolated light showers further enhanced the dispersion process between Monday and Tuesday to westerly winds, allowing clear conditions over Mumbai. On Wednesday, significant rise in rain activity also helped clear more pollutants from Mumbai’s air,” said Gufran Beig, project director, SAFAR.

“AQI is likely to remain low as long as showers continue in the city.”

PM2.5 concentration was also the lowest so far this year, with 11 micrograms per cubic metre (µg/m3) against the safe limit of 60µg/m3 for 24 hours. For Wednesday and Thursday, the concentration is likely to rise to 18µg/m3.

First Published: Jul 25, 2019 00:52 IST