Delhi's air quality remains 'very poor'

New Delhi: Delhi's air quality remained 'very poor' Thursday, with seven areas recording 'severe' air quality due to unfavourable weather conditions like low wind speed, according to authorities. The Central Pollution Control Board (CPCB) recorded an overall air quality index (AQI) of 355.

An AQI between 201 and 300 is considered 'poor', 301 and 400 'very poor' and 401 and 500 is 'severe'. The air quality in four areas –Anand Vihar, Ashok Vihar, Mundka, Nehru Nagar, Rohini, Vivek Vihar and Wazirpur –was recorded in 'severe' category. It was 'very poor' in 21 areas and 'poor' in three areas, the CPCB said.

The overall PM2.5 (fine particulate matter in the air with a diameter of less than 2.5 micrometre) level was recorded at 213 and the PM10 level at 397, it said.

In NCR, Ghaziabad recorded worst air quality in 'severe' category at an AQI of 409. Faridabad and Noida recorded 'very poor' air quality, the CPCB said.

The Centre-run System of Air Quality and Weather Forecasting (SAFAR) said the overall air quality of Delhi continues to remain in the 'very poor' range. "The overall air quality over Delhi continues to remain 'very poor'. it will remain in 'very poor' category with small fluctuations in the next three days. Meteorological conditions are improving but not yet fully favourable," it said.

According to the Indian Institute of Tropical Meteorology, the maximum ventilation index was likely around 7,500 sqm/second on Thursday. A ventilation index lower than 6,000 sqm/second with average wind speed of less than 10 kmph is unfavourable for dispersion of pollutants, it said.