POLLUTION

Looking Beyond Delhi: CSE Report Flags Rising Winter Pollution In Megacities Like Mumbai, Bengaluru, Kolkata

Polluted air engulfs Mumbai's coastline. (Shailesh Jadhav/BCCL Mumbai) — Representational Image
(Shailesh Jadhav/BCCL Mumbai)

When speaking of air pollution, the first Indian city that comes to everyone’s minds is Delhi. Toxic air has become sort of a permanent feature that the national capital has struggled to eliminate. But now, the latest trends suggest the other megacities across the country aren't too far behind.

A new report by the Centre for Science and Environment (CSE) has revealed that irrespective of their geo-climatic zones, all Indian megacities faced worsening PM 2.5 levels this winter.

CSE analysed real-time PM2.5 data from October 2022 to February 2023 in six megacities — Delhi, Kolkata-Howrah, Mumbai, Hyderabad, Bengaluru and Chennai.

Delhi, with a winter average PM2.5 level of 151 µg/m³, was unsurprisingly found to lead this group by a notable margin. However, the capital city did see some improvement this time around — its winter air was 9% less polluted this year, making the winter of 2022-23 the least polluted Delhi has experienced in the last five years.

In contrast, the remaining five megacities registered higher seasonal PM2.5 averages this winter compared to the previous one.

Kolkata and Mumbai bagged the top spots after Delhi with average winter PM2.5 levels of 84 and 77 µg/m³, respectively. This significantly exceeds the 24-hour PM2.5 standard, pegged at 60 µg/m³.

While Bengaluru, Chennai and Hyderabad found themselves below this standard at 44, 42 and 59 µg/m³, respectively, they were still above the annual average PM 2.5 levels of 40 µg/m³.

Compared to last year, winter pollution levels spiked by 14% in Mumbai and 3% in Hyderabad, while Kolkata recorded the same levels as last year. The highest increase was seen in Bengaluru and Chennai, with 15% more toxicity in the air compared to the average of their last three winters.

In terms of AQIs, with Delhi excluded, Kolkata witnessed the highest number of "very poor" AQI days (AQIs between 301-400) this winter, while Mumbai enjoyed the least number of ‘good’ AQI days (AQIs between 0-50).

"The rising winter air pollution in other megacities does not get adequate attention. These cities located outside the northern plains may have more favourable meteorological conditions to contain the peaking of pollution during winters, but their overall city average and levels across locations can cause very high exposures," Anumita Roychowdhury, executive director-research and advocacy, CSE, told The Times of India.

The situation demands stringent round-the-year action to control emissions, especially at the rapid urbanisation rate. Otherwise, 'good' air quality days quickly disappearing from these cities could soon turn into old tales from the ‘good times’.

(With inputs from TOI)

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