Pollutants PM 2.5 and PM 10 remained prominent in the air of the five immediate neighbours of Delhi, according to the air quality index (AQI) maintained by the Central Pollution Control Board (CPCB).
According to the index, 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''.
The average 24-hour AQI at 4 pm on Sunday was 390 in Ghaziabad, 322 in Noida, 388 in Greater Noida, 353 in Faridabad and 300 in Gurgaon, according to CPCB''s Sameer app.
On Saturday, it was 314 in Ghaziabad, 325 in Noida, 319 in Greater Noida, 266 in Faridabad and 285 in Gurgaon.
The CPCB states that an AQI in the ''very poor'' category may cause respiratory illness on prolonged exposure, while that in the ''poor'' zone causes breathing discomfort to most people on prolonged exposure.
The AQI for each city is based on the average value of all monitoring stations there. Ghaziabad, Gurgaon and Noida have four such stations while Greater Noida and Faridabad have two stations each, according to the app. PTI KIS IJT
Disclaimer :- This story has not been edited by Outlook staff and is auto-generated from news agency feeds. Source: PTI