New Study Reveals Air Pollution Trends in India’s Major State Capitals
In a recent study, researchers analyzed the concentrations of PM 2.5 between 2019 and 2023 in India’s major state capitals, which are known to face significant air pollution challenges. The cities included in the study were Delhi, Mumbai, Chennai, Kolkata, Bengaluru, Lucknow, and Patna.
The findings showed that Delhi, Mumbai, Hyderabad, and Kolkata experienced higher levels of PM 2.5 in October 2023 compared to the previous year. On the other hand, Chennai was found to be the least polluted city, with a decrease of over 23 percent compared to the previous year.
Delhi, which has consistently struggled with air pollution, had the highest PM 2.5 level in October 2023 among the cities analyzed. This continues a rising trend since 2021, with a sharp increase of 32 percent between 2019 and 2020, followed by a dip of 43.7 percent in 2021, and a steady rise in 2022 and 2023.
The study also revealed that the air quality in Delhi deteriorated by 4.4 percent in the last year, reaching 113.9 micrograms per cubic meter (μg/m3) in October 2023. This level was 3.7 times higher than the ‘safe’ limit of 30 μg/m3 set by the Central Pollution Control Board and 7.5 times higher than the safe limit of 15 μg/m3 recommended by the World Health Organization.
Mumbai, another highly populated city, has witnessed a continuous increase in PM 2.5 levels from 2019 to 2023, indicating a significant decline in air quality. Last month, pollution spiked by over 42 percent compared to October of the previous year. In earlier years, PM 2.5 levels fluctuated, with a 54.2 percent increase in 2019-2020, followed by a slight decrease in 2021 and 2022.
Hyderabad and Kolkata also experienced an increase in October PM 2.5 levels in 2023 compared to the previous year. In Hyderabad, levels increased by 18.6 percent in 2023, but had seen fluctuations in previous years, including a 59 percent increase in 2019-2020, a slight dip in 2021, and a significant decrease in 2022. Similarly, Kolkata witnessed fluctuations, with a dip of 33.1 percent in 2022 and a rise of 40.2 percent in 2023.
On a positive note, four state capitals, namely Lucknow, Patna, Bengaluru, and Chennai, saw a decrease in October PM 2.5 levels between 2022 and 2023. In Lucknow, levels decreased by 0.9 percent in 2023 after a period of fluctuations since 2019. Patna also experienced a decline of 11.1 percent in 2023 after significant spikes in previous years.
In Bengaluru, PM 2.5 levels decreased by 11.6 percent in 2023 after a period of fluctuations, including a significant increase in 2019-2020, a slight decrease in 2021, and another increase in 2022. Similarly, Chennai witnessed a decrease of 23.7 percent in 2023, with fluctuations in previous years.
These findings shed light on the continuing air pollution challenges faced by India’s major state capitals. Efforts to tackle this issue are crucial to safeguard the health and well-being of the population and create a cleaner and healthier environment for all.

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