The air quality remained "poor" in Gurugram. (File)
The air quality in Noida, Greater Noida, Ghaziabad and Faridabad remained "very poor" and "poor" in Gurugram in the National Capital Region (NCR) on Tuesday, according to a government agency.
Concentration of major air pollutants PM 2.5 and PM 10 also 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 was 356 in Greater Noida, 340 in Ghaziabad, 270 in Gurgaon, 321 in Noida and 318 in Faridabad, according to the CPCB's Sameer app at 4 pm on Tuesday.
It was 310 in Greater Noida, 356 in Ghaziabad, 304 in Gurugram, 399 in Noida and 298 in Faridabad, according to the CPCB's Sameer app at 4 pm on Monday.
PM 2.5 and PM 10 were prominent pollutants in Faridabad, Noida and Greater Noida, while it was PM 2.5 alone in Ghaziabad and Gurugram, according to the app.
All five satellite cities of Delhi have four air quality monitoring stations except for Greater Noida, which has two. The AQI for each city is based on the average value of all stations there, according to the app.
The CPCB states that an AQI in the "very poor" category can lead to respiratory illness on prolonged exposure, while "poor" can cause breathing discomfort to most people on prolonged exposure.