India, Nov. 7 -- Delhi's overall air quality index (AQI) remained in the 'very poor' category on Saturday morning, with a reading of 365 a day before Diwali. As many as 21 monitoring stations recorded 'severe' air quality, according to the 7am update on the HT Pollution Dashboard, which tracks the average readings from all monitoring stations reported by the Central Pollution Control Board (CPCB).

The CPCB calculates the hourly AQI at each monitoring station using a running average of readings recorded over the previous 24 hours. An analysis by the HT Pollution Dashboard showed that 21 stations recorded 'severe' air quality, while 30 were in the 'very poor' category.

The 10 Delhi monitoring stations that recorded the highest AQI reading...