Delhi recorded the highest PM2.5 pollution levels in India, with an annual average concentration of 101 micrograms per cubic metre, 2.5 times the national limit and 20 times the WHO guideline, according to a new satellite-based assessment by the Centre for Research on Energy and Clean Air (CREA).

Chandigarh logged the second-highest PM2.5 level at 70 micrograms per cubic metre between March 2024 and February 2025, followed by Haryana (63) and Tripura (62). Several other states, including Assam (60), Bihar (59), West Bengal (57), Punjab (56), Meghalaya (53) and Nagaland (52), also surpassed the National Ambient Air Quality Standard (NAAQS) of 40 micrograms per cubic metre.

Overall, 447 of 749 districts, about 60 per cent breached the annual PM2.5 limit. Pollution was highly concentrated in specific regions, with Delhi and Assam each contributing 11 of the 50 most polluted districts. Bihar and Haryana followed, with seven each. Other states in the top tier included Uttar Pradesh (4), Tripura (3), Rajasthan (2) and West Bengal (2).

In several regions, every monitored district exceeded national norms, including Delhi, Assam, Punjab, Haryana, Chandigarh, Himachal Pradesh, Meghalaya, Tripura, and Jammu & Kashmir. Many others had an overwhelming majority of districts above the threshold, 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 & Nicobar Islands, and Lakshadweep were excluded due to insufficient monitoring data.

(With inputs from PTI)