Air quality 'poor' in parts of Delhi NCR

The average 24-hour AQI at 4 pm on Sunday was 280 in Ghaziabad, 311 in Greater Noida, 239 in Noida, 251 in Faridabad and 215 in Gurgaon, according to CPCB's Sameer app.

The average air quality was 'very poor' in Greater Noida and 'poor' in Ghaziabad, Noida, Faridabad and Gurgaon on Sunday, according to a 24-hour data provided by a government agency.

According to the CPCB, an AQI in the 'very poor' category may cause respiratory illness on prolonged exposure, while prolonged exposure to 'poor' quality air may cause breathing discomfort to most people. (Parveen Kumar/HT Photo)

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).

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 280 in Ghaziabad, 311 in Greater Noida, 239 in Noida, 251 in Faridabad and 215 in Gurgaon, according to CPCB's Sameer app.

On Saturday, the AQI was 348 in Ghaziabad, 360 in Greater Noida, 346 in Noida, 311 in Faridabad and 230 in Gurgaon.

According to the CPCB, an AQI in the 'very poor' category may cause respiratory illness on prolonged exposure, while prolonged exposure to 'poor' quality air may cause breathing discomfort to most people.

The AQI for each city is based on the average value of all stations there. Ghaziabad and Gurgaon have three such stations while Noida, Greater Noida and Faridabad have two stations each, according to the app.