Delhi's air quality has further declined, remaining in the 'very poor' category with AQI levels exceeding 400 in several areas. Pollution has persisted for six days, with 589 reported stubble-burning incidents across seven states, mainly in Punjab., India News, Times Now. Delhi's air quality continued to deteriorate on Saturday as air quality remained in the 'very poor' category, with the Air Quality Index (AQI) crossing the 400 mark in several parts of.