All of the top 10 most polluted cities in India today are from Bihar, according to Central Pollution Control Board's (CPCB) data. Begusarai topped the list, with an AQI of 446, followed by Bettiah (439), Samastipur (437), Chhapra (404) and Katihar (396). The other cities in the list are Motihari (391), Purnia (389), Patna (385), Muzaffarpur (383) and Bhagalpur (365).