Byrnihat, located on the Assam-Meghalaya border, ranked as the most polluted city in India in the first half of 2025 while Delhi stood a distant second, according to a new analysis.

According to the analysis by independent research organisation Centre for Research on Energy and Clean Air (CREA), Byrnihat recorded an average PM2.5 concentration of 133 micrograms per cubic metre, while Delhi’s PM2.5 levels reached twice the national ambient air quality standard at 87 micrograms per cubic metre.

Hajipur (Bihar), Ghaziabad, Gurugram, Sasaram (Bihar), Patna, Talcher (Odisha), Rourkela (Odisha) and Rajgir (Bihar) were the other cities in the top 10 most polluted list.

Aizawl in Mizoram was the cleanest city in the country in the first half of the year.