According to a recent global assessment by the Swiss air quality monitoring company IQAir, air pollution has worsened across nearly all Bengal cities except Kolkata. Durgapur and Asansol ranked 24th and 25th on the list of the world’s 25 most polluted cities, respectively. The pollution levels in these cities, which are roughly 170 kilometres northwest of Kolkata, were higher in 2024 than in 2023.

The PM2.5 levels in Durgapur increased by 46%, from 49.5 micrograms per cubic meter in 2023 to 72.3 in 2024, even though the city is part of the National Clean Air Programme (NCAP). Asansol followed, rising by 16%, from 62.4 to 72.2 micrograms. In December 2024, Durgapur recorded the highest PM2.5 concentration in the state, measuring 128.9 micrograms.

Major Cities Exceed WHO Limits Despite Investments

The study noted that PM2.5 levels in four of the seven cities under observation—Durgapur, Asansol, Barrackpore, and Howrah—were more than ten times higher than the WHO‘s recommended threshold of 5 micrograms per cubic meter. Despite an estimated investment of ₹120 crore in efforts to mitigate air pollution, this issue persists.

Air pollution levels in Barrackpore, where the global study’s first measurements were taken, stood at 58.4 micrograms, while in Howrah, they increased by 10% from 2023 to 57.1 micrograms. The national limit for PM2.5 is 40 micrograms. Pollution levels were higher than in 2023, even in Siliguri and Haldia, yet they remained below the national limit.

Officials from the state environmental control board acknowledged the worsening situation. They attributed Durgapur and Asansol’s pollution to emissions from Jharkhand, while Barrackpore was affected by pollutants from nearby brick kilns. Uncontrolled industries and limited open space were blamed for Howrah’s high pollution levels.

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Kolkata Remains India’s Second Most Polluted Metro

Kolkata remains India’s second-most polluted metropolis after Delhi, despite a slight decline in pollution levels in 2024. It ranks among the top 2% of cities with the poorest air quality in the world. NCAP has spent ₹792 crore of the ₹960 crore allotted over the last five years.

Emissions have been reduced through pollution control techniques like water spraying and the transition to gas-powered operations for roadside restaurants and textile presser units. However, academics and state authorities cautioned that reducing pollution in Kolkata won’t be possible unless emissions from the larger Indo-Gangetic plains are addressed.

Beyond dust control, environmental experts emphasized the need for a multi-sectoral strategy that tackles industrial pollution, garbage burning, and transportation emissions. Studies indicate that burning biomass and solid waste are major contributors to Kolkata’s PM2.5 levels, while ammonia emissions exacerbate the issue by generating ultrafine particulate matter.

Despite various measures, air pollution has worsened across nearly all Bengal cities, underscoring the need for stricter regulations and comprehensive environmental policies.

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