Lucknow, Oct. 21 -- The air in the Uttar Pradesh capital turned toxic a day after Diwali celebrations, with the city's Air Quality Index (AQI) reaching 419 Monday-Tuesday night, a level classified "hazardous."This is the highest AQI recorded in the past five years and comparable to pollution levels seen in major metropolitan cities like Delhi.

According to Environment Department officials, the city experienced temperatures around 23 degrees Celsius and light winds at just 4 km per hour, which allowed pollutant particles to remain trapped in the atmosphere. The AQI stood at 419 this morning but dropped to between 190 and 195 by the afternoon as weather conditions slightly improved.

Areas such as Gomti Nagar, Aliganj, Lalbagh, Charbagh, and...