Delhi remains most polluted city in last five years, says report

Air pollution increases in the country’s four major cities

Delhi has a constant rise of pollution levels since 201 Delhi has a constant rise of pollution levels since 201

While air pollution has increased in the country’s four major cities, it has fallen in state capitals like Lucknow and Patna, according to a recent report. 

The Respirer Report on analysis of air quality over the past five years indicates that while Delhi, Mumbai, Hyderabad and Kolkata saw PM 2.5 levels higher in October 2023, compared to a year ago, Chennai saw a fall of over 23 per cent compared to a year ago.

The study analysed PM 2.5 concentrations between 2019 and 2023 in eight of India’s major state capitals which face air pollution challenges. These are Delhi, Mumbai, Chennai, Kolkata, Bengaluru, Lucknow and Patna.

Delhi has a constant rise of pollution levels since 2019. The national capital saw a sharp rise in PM 2.5 levels between 2019 and 2020 (by 32 per cent), a dip in 2021 (by 43.7 per cent), and a steady increase in 2022 and 2023. 

Over the last month, Mumbai pollution spiked by over 42 per cent compared to October a year ago. In earlier years, PM 2.5 shot up between 2019 and 2020 (by 54.2 per cent), fell slightly in 2021 (by 3 per cent) and 2022 (by 0.9 per cent).

Both Hyderabad and Kolkata also saw rise in pollution levels. Between 2019 and 2020, the former saw a rise of 59 per cent, with drops in 2021 and 2022 before spiking by more than 18 per cent in 2023. 

Kolkata saw a dip in PM 2.5 levels between 2019 and 2020, but subsequently this level went up by more than 50 per cent before a slight dip in 2022 and then a 40 per cent plus rise in 2023. 

In Lucknow and Patna, October PM 2.5 levels dropped between 2022 and 2023, holding on to gains from previous years. Bengaluru and Chennai also saw similar dips. 

Chennai was the least polluted with PM 2.5 increasing between 2019 and 2020 (by 43.2 per cent), falling in 2021 (by 27.8 per cent), rising in 2022 (by 61.6 per cent) and once again decreasing in 2023 (by 23.7 per cent).

Delhi remained the most polluted. In October 2023, the PM 2.5 level level was 3.7 times the Central Pollution Control Board’s ‘safe’ limit of 30 μg/m3 and 7.5 times the World Health Organisation’s safe limit of 15 μg/m3.

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