(Eds: Updates with fresh details)
New Delhi, Jan 11 (PTI) Delhi's air quality deteriorated to the 'severe' category Friday due to reduced wind speed even as authorities have forecast rainfall in the next couple of days which they said might lower the pollution level.
According to the Central Pollution Control Board (CPCB) data, the overall air quality index (AQI) in the city was 402, which falls in the 'severe' category.
An AQI between 100 and 200 comes under the 'moderate' category, 201 and 300 is considered 'poor', 301 and 400 'very poor', while that between 401 and 500 'severe'.
Twenty-two areas recorded 'severe' air quality and 13 'very poor', the CPCB said.
In the National Capital Region (NCR), Ghaziabad, Faridabad and Greater Noida recorded 'severe' air quality, while Gurgaon 'very 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 278, while the PM10 level was at 430, it 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 rains which is expected thereafter.
"The overall air quality will deteriorate further, with small fluctuations in the next three days if it does not rain. Other meteorological conditions are not favourable although foggy conditions are likely to reduce now," the SAFAR said.
Delhi's air quality was recorded in the 'poor' category Wednesday and Thursday with increased wind speed which helps in cleansing the air before slipping into 'very poor' category on Friday morning before nosediving towards severe pollution level. PTI UZM DPB