The otherwise-busy Western Express Highway near airport which is choc-a-bloc with traffic wore a deserted look... Read More

MUMBAI: As the city slows to fight Covid-19, its air has seen a decline in pollutant levels, found a report by System of Air Quality Weather Forecasting and Research (SAFAR). According to SAFAR, there was a 45% drop in concentration of nitrogen oxide (NOx) this month compared to March 2018 and 2019. A drop in concentration of PM 2.5 too was seen since restrictions were imposed.

SAFAR’s report states, “Fossil fuel emission, mainly coming from vehicular traffic, is one of the major sources of NOx (60-80%) and PM2.5 (35-50%) in Delhi, Mumbai, Pune and Ahmedabad. Under fair weather conditions, NOx levels are mainly controlled by its major sources of emissions (vehicular traffic), although changes due to weather cannot be ruled out. Hence, if NOx levels are reduced significantly as compared to earlier years, it may provide us a qualitative/broader indication in reduction in emissions in major sources.” In Mumbai’s lowered Nox levels, the major drop of 75% was noticed at BKC. Nerul and Worli too showed a reduction. But levels at Colaba, Andheri, Malad and Mazgaon showed no change.

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SAFAR has also recorded a drop in PM 2.5 levels, concentration of which is used to calculate air quality index. Though PM 2.5 concentration in comparison with March 2018 and 2019 did not show a change, it dropped from 118 microgrammes per cubic metre (µg/m3) on Tuesday to 40 µg/m3 on Saturday. “There was a spike in pollutants during Monday and Tuesday which could be due to more people using their own vehicles in the wake of restrictions. But it soon began to drop.,” said Gufran Beig, project director, SAFAR. Saturday’s AQI for Mumbai was 64, the best in 2020. An AQI between 51 and 100 is considering to be satisfactory.

