Air quality largely remained "very poor" in parts of Gautam Buddh Nagar, Ghaziabad, Gurgaon and Faridabad in the National Capital Region on Wednesday, according to a government agency.
Concentration of major air pollutants PM 2.5 and PM 10 during the morning hours also remained either in "very poor" or "severe" categories in the four immediate neighbouring districts 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".
In Gautam Buddh Nagar's Noida, the AQI was 344 at Sector 62, 321 at Sector 116 followed by 335 at Sector 1, while the station at Sector 125 showed "insufficient" data for the last 24 hours.
In Greater Noida, an AQI of 356 was recorded at Knowledge Park V and 346 at Knowledge Park III, according to the CPCB data at 8 pm.
In Ghaziabad, an AQI of 395 was recorded at the station in Loni followed by 347 at Sanjay Nagar, 344 at Indirapuram and 318 at Vasundhara, according to the CPCB figures.
In Gurgaon, the AQI was 386 at Sector 51, 337 at Teri Gram, 323 at Vikas Sadan and 294 at NISE Gwal Pahari, it showed.
In Faridabad, the AQI was recorded at 353 at Sector 11, 329 at Sector 16A, 321 at Sector 30 and 283 at New Industrial Town at 8 pm.
As a possible health impact, the CPCB states, an AQI in the "very poor" category can lead to respiratory illness on prolonged exposure, while "poor" air can cause breathing discomfort to most people on prolonged exposure.
The Graded Response Action Plan (GRAP) has also been implemented in the Delhi-NCR region from October 15 to check air pollution, which spikes around this time of the year.
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