The average Air Quality Index (AQI) in Delhi touched 335 at 9 am, making it the most polluted city in the country, according to the Central Pollution Control Board (CPCB). The national capital has been witnessing the deteriorating air quality since Diwali. The top 10 most polluted areas in Delhi include Bawana, Vivek Vihar, Wazirpur, Mundka, Punjabi Bagh and ITO.