File photo. Photograph:( ANI )
The Air Quality Index (AQI) in Delhi was recorded as 366 on Monday falling under the very poor category.
The AQI in the city which was recorded at its worst of this season on Sunday saw a little improvement on Monday.
The overall Air Quality Index of the national capital on Sunday was recorded at 381, the highest of this season.
The air quality in Ghaziabad and Gurugram was recorded over 400 falling under the "severe category".
While the AQI in Ghaziabad was recorded at 415, that of Gurugram was 403.
The air quality in Noida and Greater Noida was recorded as very poor with 385 and 362 AQI respectively.
The severe air quality affects the healthy people and seriously impacts those with existing diseases, while the very poor air quality results in respiratory illness on prolonged exposure.
An AQI between 0 and 50 is considered "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", 301 and 400 "very poor", and 401 and 500 "severe".
Authorities attribute the dip in air quality to localised factors like construction dust, vehicular pollution as well as regional factors like pollution due stubble burning from Punjab and Haryana.