The average air quality improved from “severe” level and was recorded in “very poor” category in Delhi, Ghaziabad, Noida, Greater Noida, Faridabad and Gurgaon, according to a 24-hour data issued by a Government agency on Friday.
Presence of pollutant PM 2.5 and PM 10, though, remained high in the five immediate neighbours of Delhi, according to air quality index (AQI) maintained by the the Central Pollution Control Board (CPCB).
An AQI between zero 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”.