Vehicular pollution 60% up in Mumbai after lockdown curbs relaxed: SAFAR

System of Air Quality Weather Forecasting and Research (SAFAR) compared pollution levels between June 1 and June 14 with those recorded between May 18 and May 31, for Mumbai, Pune, Ahmedabad and Delhi.

Since lockdown restrictions were relaxed on June 1, the city has recorded a sharper rise in levels of traffic pollution than other major cities in India.

On Thursday, the air quality index (AQI) for Mumbai was 18 during the day and fell to 17 in the evening, which is the lowest of this year, said SAFAR. (Satyabrata Tripathy/HT file photo)

System of Air Quality Weather Forecasting and Research (SAFAR) compared pollution levels between June 1 and June 14 with those recorded between May 18 and May 31, for Mumbai, Pune, Ahmedabad and Delhi. Mumbai witnessed a 60% increase in nitrogen dioxide (NO2) levels (from vehicular emissions and fossil fuel burning) compared to levels recorded during the fourth phase of the lockdown, according to an analysis released by SAFAR on Thursday.

Pune and Ahmedabad witnessed less than 10% rise in NO2 levels while Delhi recorded 6% decline in NO2 even after restrictions were relaxed. “The sudden increase in vehicular traffic combined with rising industrial production may have contributed to the sudden surge in NO2 concentration over Mumbai. Also, it shows the role played by the transport sector as a major source of air pollution in the financial capital,” said Gufran Beig, director, SAFAR.

Between March 25 and April 14, Mumbai had recorded the sharpest decline in NO2 levels (72%) as compared with levels recorded during the same period in 2019 as well as concentration during the months prior to lockdown. From April 15 to May 3, the percentage reduction fell marginally but a 64% decline was recorded. The percentage reduction from May 4 to May 17 was 59% and from May 18 to May 31, it was 49%.

“However, even after an increase in NO2, the concentration of the pollutant was well within permissible limits in all four cities where SAFAR monitors air quality,” said Beig.

Mumbai witnessed 10 rainy days during the study period while Delhi, Ahmedabad, and Pune had eight rainy days each. This led to the reduction in PM 2.5 — breathable particulate matter of 2.5 micron size or smaller that can cause health ailments — in all four cities. Pune recorded the highest decline (40%), followed by Mumbai (35%), Ahmedabad (20%) and Delhi (5%). “The first two weeks of the unlock period were marked by rainy days which washed away particulate pollutants. However, the prolonged lockdown also helps in reducing background levels (when human-induced sources are minimal), which will take some time to return to earlier levels,” said Beig.

On Thursday, the air quality index (AQI) for Mumbai was 18 during the day and fell to 17 in the evening, which is the lowest of this year, said SAFAR. “Intermittent showers will allow PM levels to fall to record low levels in coming days unless there is a prolonged dry spell. Overall, good to satisfactory category is expected to continue during monsoon for all four cities,” said Beig.