India, Nov. 11 -- Delhi's struggle for clean air continues as the national capital as the air quality plummeted to 'severe' category with an overall Air Quality Index (AQI) recorded at 421 at 7 am on Tuesday.

According to data from the Central Pollution Control Board (CPCB), most parts of the city logged alarming pollution levels with the AQI going above the 400-mark.

Bawana recorded the worst AQI of 462, RK Puram and Patparganj at 446 and 438, respectively. Among other most polluted areas of Delhi were Anand Vihar with an AQI of 412, Alipur with 442, and Chandni Chowk with an AQI of 416.

Tuesday's AQI levels were marginally higher than Monday, when the AQI was in the 'very poor' category, with a recording of 345 as of 8 am.

According...