The air quality improved slightly but remained "severe" in Noida, Greater Noida, Ghaziabad, Faridabad and Gurgaon in the National Capital Region (NCR) on Tuesday, according to a government agency.
The concentration of major air pollutants PM 2.5 and PM 10 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 Tuesday was 455 in Noida, 448 in Faridabad, 444 in Ghaziabad, 436 in Greater Noida and 427 in Gurgaon, according to the CPCB's Sameer app.
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.
PM 2.5 and PM 10 were the prominent pollutants in these satellite cities of Delhi, according to the app.
The CPCB states that an AQI in the "severe" category "affects" healthy people and "seriously impacts" those with existing diseases.
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.
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