New Delhi, Jan 12 (IANS): Owing to a rise in humidity and light winds, the overall air quality of the national capital slipped to the 'severe' zone on Saturday, despite the authorities predicting it would remain in the 'very poor' category.

"Calm winds along with a spike in humidity levels because of an induced Cyclonic Circulation over Northern Plains are the major contributors for a hike in pollution levels in Delhi and adjoining areas," Mahesh Palawat, Director at private weather forecasting agency Skymet told IANS.

He said that the pollution levels might increase in the coming days as humidity levels are expected to go up due to rains in Punjab, Haryana and Rajasthan.

"Around January 13 and 14, moderate to dense fog is expected to make a comeback, which will result in high pollution levels and minimums will see a drop by a couple of degrees," he said.

However, the Skymet Director said that post January 15, the air quality might start improving due to cold, north-westerly winds which will blow over the plains of the country.

The System of Air Quality and Weather Forecasting And Research (SAFAR), in its daily pollution analysis, has been maintaining that the air quality in Delhi won't go beyond the 'very poor' category.

On Saturday however, many areas in Delhi and adjoining areas at 12 p.m recorded 'severe' levels of toxic particulate matter (PM) 2.5.

Anand Vihar at 448, Dwarka sector-8 at 450, ITO at 413, Mundka at 438, Delhi University North Campus at 416, R.K. Puram at 415, and Wazirpur at 434 - all recorded 'severe' levels of PM2.5.

Other areas like Jawaharlal Nehru Stadium, Ashok Vihar, Burari Crossing, Vivek Vihar, Sirifort, Okhla Phase-2 also fared in the same category.

On Wednesday and Thursday, Delhi-NCR witnessed its first better days of the year with the air quality recorded in the 'poor' zone.

The India Meteorological Department (IMD) has forecast light rainfall at isolated places in Delhi over the weekend which might bring down pollution levels.