Delhi's air quality remained in the 'very poor' category for the fourth consecutive day on Thursday due to "unfavourable meteorological conditions" that slowed down dispersion of pollutants even as thick haze engulfed the city, authorities said.
However, improvements were recorded in PM2.5 and PM10 readings in the national capital.
The overall air quality index (AQI) of Delhi was recorded at 335, according to the 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 25 areas of Delhi recorded 'very poor' air quality while 11 areas recorded 'poor' air quality.
The level of PM2.5 -- particles in the air with a diameter of less than 2.5 micrometres -- was recorded at 165 and the PM10 level was recorded at 282, it said.
In NCR, Ghaziabad, Faridabad and Noida recorded 'very poor' air quality while Gurgaon fell into the 'poor' category, the CPCB data showed.
Meanwhile, in order to combat air pollution, the Delhi government on Tuesday released the draft of Delhi Electric Vehicle Policy 2018 for public comments.
"About 30 per cent of particulate pollution in winter is caused by vehicles. A rapid adoption of zero-emission electric vehicles is therefore of great importance to Delhi. Recognising the need for a new approach to kick-start electric vehicle adoption, we have drafted a comprehensive Delhi Electric Vehicle Policy with an aim to make Delhi a leader in the adoption of electric vehicles. We believe that going electric and breathing better are two sides of the same coin," Transport Minister Kailash Gahlot said in a statement.
According to the Centre-run System of Air Quality and Weather Forecasting (SAFAR), the air quality is 'very poor' and likely to improve due to a slight increase in wind speed but will remain in 'very poor' for the next two days and then increase.
"Due to cold front up in the north, the wind speed has increased so a decline (in pollution) is expected. However, at the time of withdrawal after two to three days, a lot of moisture may enter Delhi which is not favourable for the air quality. The contribution from stubble biomass is nil," the SAFAR said.