The air quality remained “moderate†in Faridabad but slipped to “poor†level in Gurgaon, Noida, Greater Noida and Ghaziabad on Saturday, according to a government agency.
Presence of 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).
As per the index, an AQI between 0 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 Saturday was 171 in Faridabad, 204 in Gurgaon, 233 in Noida, 226 in Greater Noida and 240 in Ghaziabad, according to CPCB's Sameer app.
On Friday, it was 107 in Gurgaon, 125 in Noida, 129 in Greater Noida, 134 in Faridabad and 166 in Ghaziabad.
On Thursday, it was 301 in both Ghaziabad and Noida, 296 in Greater Noida, 312 in Faridabad and 299 in Gurgaon.
On Wednesday, it was 444 in Ghaziabad, 414 in Noida, 394 in Greater Noida, 348 in Faridabad and 299 in Gurgaon.
According to the CPCB, an AQI in the "moderate" category may cause breathing discomfort to people with lung, asthma and heart 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.
