Delhi's air quality deteriorated to 'very poor' category on Friday due to reduced wind speed even as authorities said rainfall predicted in the next couple of days might lower the pollution level.
According to Central Pollution Control Board (CPCB) data, the overall air quality index (AQI) in the city was 348, which falls in the 'very poor' category.
An AQI between 100 and 200 comes under 'moderate' category, 201 and 300 is considered 'poor', 301 and 400 'very poor', while that between 401 and 500 is 'severe'.
Mundka, ITO and Nehru Nagar recorded 'severe' air quality, while 30 areas recorded 'very poor' air quality and four areas 'poor' air quality, the CPCB said.
In the National Capital Region (NCR), Ghaziabad, Faridabad and Noida recorded 'very poor' air quality while Gurgaon recorded 'poor' air quality, it said.
The overall PM2.5 level (fine particulate matter in the air with a diameter of less than 2.5 micrometers) in Delhi was recorded at 247, while the PM10 level was at 396, the CPCB said.
The Centre-run System of Air Quality and Weather Forecasting (SAFAR) said the air quality may improve in the next two days under the influence of light rain which is expected thereafter.
Delhi's air quality was recorded in the 'poor' category on Wednesday and Thursday with increased wind speed which help in cleansing the air.