Delhi air deteriorates to 'very poor' due to calm winds, average AQI at 355

After a two-day gap, Delhi's air quality turned 'very poor' again on Sunday as calm winds prevented dispersion of pollutants. Some areas in the national capital recorded 'severe' pollution levels. Delhi's 24-hour average Air Quality Index (AQI) was recorded at 355 at 4 pm as against 255 on Saturday, Central Pollution Control Board (CPCB) data showed. Data from 37 of the city's 40 monitoring stations was shared by the CPCB. It showed that three stations -- Bawana, Burari and Jahangirpuri -- recorded 'severe' air quality. The air quality was also 'very poor' in Delhi's neighbouring areas like Greater Noida, Ghaziabad and Noida and 'poor' in Faridabad and Gurugram. Under the Graded Response Action Plan (GRAP), a set of emergency measures to control air pollution in the Delhi-NCR region during winter, air quality is categorised into four stages: Stage I -- "Poor" (AQI 201-300); Stage II -- "Very Poor" (AQI 301-400); Stage III -- "Severe" (AQI 401-450); and Stage IV -- "Severe Plus" (AQ