Ghaziabad and Delhi ranked most polluted Indian cities in January 2026 by CREA

Key facts

• Ghaziabad was the most polluted city in India in January 2026, recording a monthly average PM2.5 concentration of 184 micrograms per cubic metre.
• Delhi ranked as the second most polluted city with a monthly average PM2.5 concentration of 169 micrograms per cubic metre, nearly three times the National Ambient Air Quality Standards (NAAQS) limit of 60 micrograms per cubic metre.
• According to the Centre for Research on Energy and Clean Air (CREA), Delhi recorded 24 Very Poor days, 3 Severe days, 2 Poor days, and 2 Moderate days during the month.
• The Central Pollution Control Board (CPCB) defines Air Quality Index (AQI) categories as Good (0-50), Satisfactory (51-100), Moderate (101-200), Poor (201-300), Very Poor (301-400), and Severe (401-500).
• Across India, 123 out of 248 cities recorded monthly average PM2.5 concentrations above the national standard, and none met the World Health Organization (WHO) daily safe guideline of 15 micrograms per cubic metre.
• Of the 97 cities under the National Clean Air Programme (NCAP) with sufficient data, all 97 breached the WHO daily safe guideline.
• The ten most polluted cities in January 2026 were Ghaziabad, Delhi, Noida, Gurugram, Greater Noida, Dharuhera, Gangtok, Singrauli, Bhiwadi, and Narnaul.
• Uttar Pradesh and Haryana each had three cities featured in the top ten most polluted list.
• PM2.5 are defined as fine particles with a diameter of 2.5 micrometres or less that can penetrate deep into the lungs and enter the bloodstream.