Noida (UP), Feb 19 (PTI) The average air quality in Ghaziabad, Noida, Greater Noida and Gurgaon was recorded 'very poor', while it was 'poor' in Faridabad, according to data issued by a government agency on Friday.
Pollutants PM2.5 and PM10 also remained 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 Friday was 352 in Ghaziabad, 324 in Noida, 304 in Greater Noida, 288 in Faridabad and 338 in Gurgaon, according to CPCB's Sameer app.
The AQI for Ghaziabad, Noida and Greater Noida was recorded 'very poor' for a fifth day in a row, it showed.
On Thursday the AQI was 325 in Ghaziabad, 315 in Noida, 336 in Greater Noida, 307 in Faridabad and 296 in Gurgaon.
On Wednesday it was 328 in Ghaziabad, 322 in Noida, 337 in Greater Noida, 307 in Faridabad and 316 in Gurgaon.
On Tuesday it was 356 in Ghaziabad, 335 in Noida, 375 in Greater Noida, 310 in Faridabad and 302 in Gurgaon.
On Monday it was 369 in Ghaziabad, 368 in Noida, 349 in Greater Noida, 353 in Faridabad and 306 in Gurgaon.
On Sunday it was 416 in Ghaziabad, 416 in Noida, 402 in Greater Noida, 366 in Faridabad and 288 in Gurgaon.
The CPCB states that an AQI in the 'very poor' category may cause respiratory illness to people on prolonged exposure, while that in the 'poor' zone may cause 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 CK