Delhi's air quality was in the 'very poor' category Friday due to adverse meteorological conditions that slowed dispersion of pollutants, with agencies forecasting "significant deterioration" in pollution levels over the weekend.
The overall air quality index (AQI) of Delhi was 349, according to Central Pollution Control Board (CPCB) data, .
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 CPCB said in 26 areas the air pollution level was in the 'very poor' category.
The level of PM2.5 (particles in the air with a diameter of less than 2.5 micrometre) was recorded at 187 and the PM10 level was recorded at 338, it said.
In NCR, Ghaziabad, Faridabad and Noida recorded 'very poor' air quality while Gurgaon recorded moderate air quality, the CPCB data said.
According to the Indian Institute of Tropical Meteorology, the maximum ventilation index is likely to be 9000 sqm/second on Friday and decrease to 5000 sqm/second on Saturday.
According to the Centre-run System of Air Quality and Weather Forecasting (SAFAR), the air quality is very poor and likely to remain in the same category with slight decline by Saturday due to enhanced wind speed.
"However, it is likely to increase thereafter for the next two days to register in upper range of very poor level. This deteriorating AQI on December 2-3 is mainly due to expected adverse meteorological conditions and decline in wind speed. The contribution from long range dust or stubble biomass is negligible," it said.
(With inputs from agencies.)