E-Paper
Delhi was India's second most polluted city for fourth consecutive month in Jan. Who topped the list?
Bihar was home to three most polluted cities in the top 10. It also has the highest number of cities, 21 out of 24, that breach national air quality standards.
Delhi emerged as the second most polluted city in India for the fourth consecutive month in January, according to a report the Centre for Research on Energy and Clean Air (CREA).
The report said that Delhi recorded an average PM2.5 concentration of 165 micrograms per cubic metre in January 2025. “Throughout January, Delhi experienced 23 days in the ‘very poor’ category, three days fell into the ‘severe’ category (>250 µg/m³), three days in poor category and two days in moderate category,” the report said.
Byrnihat, an industrial town in Meghalaya on the border with Assam, was ranked the most polluted Indian city last month. The northeast city recorded an average PM2.5 concentration of 214 µg/m³.
Other most polluted Indian cities in the top 10 are Hajipur, Talcher, Patna, Chandigarh, Guwahati, Barrackpore, Muzaffarpur, and Howrah. Bihar was home to three most polluted cities in the top 10. The state also has the highest number of cities, 21 out of 24, that breach national air quality standards.
“Alarmingly, none of the top 10 most polluted cities recorded even a single day within the safe daily National Ambient Air Quality Standards (NAAQS) threshold throughout January,” the report said.
The independent research organisation said that 105 out of 240 Indian cities exceeded the PM2.5 NAAQS limit of 60 micrograms per cubic metre in January.
“Among these, 71 cities recorded ‘moderate’ PM2.5 Air Quality Index (61-90 µg/m³) category, while 31 cities fell under the ‘poor’ category (91-120 µg/m³). The remaining three cities experienced ‘very Poor' category conditions (121-250 µg/m³),” the report added.
Mizoram's Aizawl emerged the cleanest city of the month with average PM2.5 concentration of just 9 µg/m³.
Manoj Kumar, Analyst at CREA, noted that, “While Delhi’s PM2.5 concentration in January 2025 was lower than the 206 µg/m³ recorded in January 2023, it still remains 2.5 times above the NAAQS and 11 times higher than the World Health Organization (WHO) standard. Several GRAP measures were imposed during the month, but attributing the improvement to GRAP requires a clearer understanding of the actual actions implemented on the ground. Transparency in GRAP execution is essential to ensure accountability, assess its impact, and refine future air pollution control strategies.”
