The average air quality remained "poor" in the NCR (National Capital Region) cities of Ghaziabad, Noida, Greater Noida, Faridabad and Gurgaon for a second day in a row, according to a 24-hour data issued by a government agency on Tuesday. Presence of pollutant PM 2.5 and PM 10 remained high in 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 Tuesday was 283 in Ghaziabad, 272 in Greater Noida, 258 in Noida, 291 in Faridabad and 214 in Gurgaon, according to CPCB's Sameer app. The CPCB states that an AQI in the "poor" category may cause breathing problem to people on prolonged exposure.
The average AQI on Monday was 256 in Ghaziabad, 237 in Greater Noida, 225 in Noida, 296 in Faridabad and 226 in Gurgaon. On Sunday, it was 407 in Ghaziabad, 418 in Greater Noida, 405 in Noida, 404 in Faridabad and 359 in Gurgaon.
The AQI for each city is based on the average value of all stations there. Noida, Faridabad, Ghaziabad have four stations each while Gurgaon has three and Greater Noida two, according to the app.