Noida (UP), Nov 11 (PTI) The air quality improved from 'severe' to 'very poor' category in Noida, Greater Noida, Ghaziabad and Faridabad, and 'poor' in Gurgaon in the National Capital Region (NCR) on Wednesday, according to a government agency.
Although concentration of major air pollutants PM2.5 and PM10 remained high in the five immediate neighbours of Delhi, according to the air quality index (AQI) maintained by 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'.
The average 24-hour AQI at 4 pm on Wednesday was 360 in Ghaziabad, 340 in Greater Noida, 327 in Faridabad, 309 in Noida, and 288 in Gurgaon, according to the CPCB's Sameer app.
The Tuesday's average AQI was 455 in Noida, 448 in Faridabad, 444 in Ghaziabad, 436 in Greater Noida and 427 in Gurgaon – all five in the 'severe' category.
On Monday it was 482 in both Gurgaon as well as Ghaziabad followed by 478 in Greater Noida, 477 in Noida and 456 in Faridabad.
PM2.5 and PM 10were the prominent pollutants in these satellite cities of Delhi on Wednesday, according to the app.
The CPCB states that an AQI in the 'very poor' category may cause respiratory illness on prolonged exposure, while 'poor' may lead to breathing discomfort to most people on prolonged exposure.
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. PTI KIS CK