Delhi most polluted megacity but THESE 2 cities experienced worst peak pollution in last 4 yrs. Details here

Amid the rise in influenza A (H3N2) cases in the country, a report by Centre for Science and Environment (CSE) has stated that all mega cities in India, irrespective of their locations in different geo-climatic zones, faced the challenge of worsening PM2.5 levels during the winter season of 2022-23.

Also Read: Influenza H3N2 rise in Delhi leads to 25% surge in anti-allergy medicines' sales: Report

The assessment of annual and seasonal trends in PM2.5 concentrations for the period October 1 to 28 February for the years 2019-20, 2020-21, 2021-22 and 2022-23 from Delhi, Kolkata-Howrah, Mumbai, Hyderabad, Bengaluru and Chennai. “The objective of this analysis has been to assess the peer megacities to understand the longer term seasonal variations and annual trends in particulate pollution,” it stated.

The report showed that Delhi, with a winter average PM2.5 level of 151 µg/m³ remains the most polluted megacity by a large margin, though it has shown improvement over the past few year.

Among the mega cities, Kolkata and Mumbai as per the report are the most polluted after Delhi. The report also stated that air quality has worsened fastest in Bengaluru and Chennai.

Also Read: Toxic skies: This region has world's worst air quality

 "Compared to winter of 2021-22 only Delhi has shown improvement in winter air quality and its winter air is 9 percent less polluted than previous winter. But the winter average of PM2.5 average has increased in rest of the five megacities, it showed.

Also Read: Covid, Influenza cases rising in India in past few days: Do we need to worry?

It also said that when PM2.5 level of the current winter is compared with the average for the previous three winters, Bengaluru and Chennai’s performance is the worst as their winter air is 15 percent more polluted than average of their previous three winters. Mumbai’s winter air is 14 percent more polluted while Hyderabad’s winter air is 3 percent more polluted. The report stated that peak winter pollution in Bengaluru and Hyderabad is worst in last four years. 

Meanwhile, Kolkata’s overall winter average of PM2.5 improved compared to previous three years but is stagnating since last year. Kolkata’s winter air is 7 per cent less polluted compared to the average of previous three winters, but this winter’s pollution level is identical to last winter level showing a stagnant trend, as per the report.

If Delhi is excluded, then Kolkata had the highest number of “very poor” AQI days this winter while Mumbai had the least number of “good” AQI day.

Speaking of specific location, during October-February 2022-2023, the report states that in Kolkata-Howrah, the most polluted location was Ghusuri in Howrah with a PM2.5 level in winter at 128. In Mumbai, the worst air quality was recorded at Bandra-Kurla Complex (BKC) whose seasonal average stood at 122. Alandur in Chennai was the most polluted location in Chennai with a seasonal average of 71. Zoo Park was the worst affected in Hyderabad with a seasonal average of 71 while in Bengaluru the most polluted location was Bapuji Nagar – the seasonal average was 64.

AnumitaRoychowdhury, executive director-research and advocacy, CSE, said, “While Delhi’s winter air quality hogs all the eyeballs, the rising winter air pollution in other mega cities including Kolkata, Mumbai, Hyderabad, Bengaluru and Chennai, does not get adequate attention. While Delhi has bent its seasonal pollution curve, winter air pollution is high or on the rise in most other megacities."

Recently, a recent study published in Lancet Planetary Health suggested that less than 1 percent of the world's population breathe pollution-free air. 

The research found that about 99.82 percent of the global land area is exposed to dangerous levels of particulate matter 2.5 (PM2.5), which exceeds the safety limit recommended by the World Health Organisation (WHO). The study found that air quality is particularly worrisome in regions such as south Asia and east Asia, where more than 90 percent of days had PM2.5 concentrations above the 15 microgram threshold. The highest concentrations of PM2.5 were found in east Asia, followed by south Asia and North Africa, while regions in Oceania and southern America had the lowest annual PM2.5 concentrations.