A thick layer of smog often shrouds New Delhi: The capital ranks as the most polluted among 33 states and Union Territories in the country, with the highest annual average PM2.5 level at 101 micrograms per cubic metre. File photo
CREA study finds Delhi most polluted; 60 pc of districts analysed breach PM2.5 norm
CREA study shows pollution levels in Delhi is 2.5 times Indian Standard, 20 times higher than WHO; Chandigarh records second highest levels
Delhi ranks as the most polluted among 33 states and Union Territories in the country, with the highest annual average PM2.5 level at 101 micrograms per cubic metre. The level of pollution is 2.5 times the Indian Standard and 20 times higher than the World Health Organisation (WHO) guideline.
These figures form part of a recent report from the Centre for Research on Energy and Clean Air (CREA).
The new satellite-based analysis by the independent research organisation CREA revealed that Chandigarh recorded the second-highest annual average PM2.5 level at 70 micrograms per cubic metre, followed by Haryana at 63, and Tripura at 62. The study was conducted from March 2024 to February 2025.
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Several other states also exceeded the national standard, including Assam (60), Bihar (59), West Bengal (57), Punjab (56), Meghalaya (53), and Nagaland (52).
Overall, 447 of the 749 districts (60 per cent) analysed breached the National Ambient Air Quality Standard (NAAQS) for annual PM2.5 of 40 micrograms per cubic metre.
Most polluted districts
As per the report, the most polluted districts were heavily concentrated in a few states. According to the analysis, Delhi (11 districts) and Assam (11 districts) together accounted for nearly half of the top 50, followed by Bihar (7) and Haryana (7). Other contributors include Uttar Pradesh (4), Tripura (3), Rajasthan (2) and West Bengal (2).
In Delhi, Assam, Punjab, Haryana, Chandigarh, Himachal Pradesh, Meghalaya, Tripura and Jammu and Kashmir, all monitored districts exceeded the NAAQS.
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Several other states showed a large majority of districts breaching the standard, such as Bihar (37 of 38), West Bengal (22 of 23), Gujarat (32 of 33), Nagaland (11 of 12), Rajasthan (30 of 33) and Jharkhand (21 of 24).
Ladakh, Andaman and Nicobar Islands, and Lakshadweep were excluded from the analysis due to insufficient ground monitoring data during the study period.