Mumbai experiences least polluted post Diwali air since 2015

The AQI on the day after Diwali was 319 in 2017, 320 in 2016 and 313 in 2015, all under the ‘very poor’ category

Even though the city recorded a spike in pollutants on Thursday, pollution levels on the day after Diwali were the lowest since 2015 when air quality monitoring began in Mumbai.

Children celebrate Diwali at Parel. (Satyabrata Tripathy/HT Photo)

The System of Air Quality Weather Forecasting and Research (SAFAR) recorded the air quality index (AQI) — a measure of pollution — on Thursday at 305 (very poor). The AQI on the day after Diwali was 319 in 2017, 320 in 2016 and 313 in 2015, all under the ‘very poor’ category.

On Thursday, Andheri was the most polluted location with a ‘severe’ AQI of 447 followed by Mazagaon at 355 (very poor). The city had recorded an AQI of 221 (poor) on Wednesday (Diwali).

An AQI from 0-50 is considered good, 51-100 is satisfactory, 101-200 is moderate, 201-300 is poor, 301-400 is very poor, and 401 and above is severe.

On Friday, SAFAR released a report where researchers said a combination of weather factors and low emission from firecrackers resulted in less pollution.

“As compared to previous years, air quality in Mumbai this Diwali has been the best. In November, temperatures are lower, which automatically suspends pollutants closer to the surface. This year, the same phenomenon did not sustain for long, which indicates that emission from firecrackers was less. Simultaneously, moderate wind speed from north-easterly winds did not allow pollutant particles to settle close to the surface for long, and expedited the dispersion process” said Gufran Beig, project director, SAFAR.

The SAFAR’s Diwali report said PM2.5 — small particles predominantly 2.5 microns in size that can penetrate deeper into the lungs and enter the bloodstream — was the most prominent pollutant in Mumbai. “The highest levels of PM2.5 was observed between 10pm and 4am late on Wednesday and early on Thursday,” read the report. The report added, “While Andheri and Mazagaon were the most polluted sites a day after Diwali, Bhandup and Chembur were least polluted.” On Friday, the air quality improved and entered the ‘poor’ category with AQI recorded at 242.

Meanwhile, the Central Pollution Control Board’s (CPCB) countrywide assessment showed that Diwali air quality was better in Mumbai than other cities.