Mumbai’s air quality turns ‘poor’ for first time this season

On Thursday, the prominent pollutant in the air was PM2.5 — particulate matter of 2.5-micron size – which can easily enter the lungs and cause breathing ailments.

The Air Quality Index (AQI) for Mumbai entered the ‘poor’ category on Thursday – a first for this season. AQI, the pollution measuring indicator recorded at 10 stations in Mumbai, was 217 (poor) during the day and 202 (poor) in the evening, according to the Central Pollution Control Board (CPCB)

Smog seen at Girgaum Chowpatty in Mumbai, on Thursday, November 21, 2019. (Kunal Patil/HT Photo)

AQI in the 0-50 range is considered ‘good’; 51-100 is ‘satisfactory’; 101-200 is ‘moderate’; 201-300 is ‘poor’; 301-400 is ‘very poor’; anything above 400 is ‘severe’.

The last time city’s AQI was in the ‘poor’ category was on March 24, when the System of Air Quality Weather Forecasting and Research (SAFAR) had measured it at 254. There is, however, no historical data available from CPCB for Mumbai, as they have begun releasing AQI figures only this season.

On Thursday, the prominent pollutant in the air was PM2.5 — particulate matter of 2.5-micron size – which can easily enter the lungs and cause breathing ailments.

Researchers from CPCB and SAFAR said that owing to gradual decline in temperatures, drop in moisture and low wind speed, the surface layer boundary of pollutants were suspended closer to the surface. “As temperature continues to fall, this boundary layer will get stronger in coming days,” said a CPCB scientist.

The concentration of PM2.5 was 86 microgrammes per cubic metre (µg/m3) on Thursday against the safe limit of 60 µg/m3, and concentration for PM10 (larger coarser particles) was 178 µg/m3 against the safe limit of 100 µg/m3.

“This is the effect of winter setting in over the city and air quality is expected to be at the borderline of ‘moderate’ and ‘poor’ in coming days till the end of the month,” said Gufran Beig, project director, SAFAR.

Location wise data from SAFAR showed that Bandra Kurla Complex was the most polluted with ‘very poor’ AQI of 311, followed by Nerul, Navi Mumbai at 239 (poor); and Colaba 206 (poor).