Noida (UP), Feb 4 (PTI) The air quality in Ghaziabad, Noida, Greater Noida, Faridabad and Gurgaon remained 'very poor' for the third day in a row, according to data issued by a government agency on Thursday.
Pollutant PM 2.5 and PM 10 also 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 Thursday was 338 in Ghaziabad, 322 in Noida, 312 in Greater Noida, 308 in Faridabad and 303 in Gurgaon, according to CPCB's Sameer app.
The CPCB states that an AQI in the 'very poor' category may cause respiratory illness on prolonged exposure.
On Wednesday, it was 388 in Ghaziabad, 339 in Noida, 345 in Greater Noida, 317 in Faridabad and 306 in Gurgaon.
On Tuesday, it was 394 in Ghaziabad, 372 in Noida, 379 in Greater Noida, 354 in Faridabad and 324 in Gurgaon.
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 TDS TDS