New Delhi, Dec 26 (IANS): Air quality in the national capital improved slightly on Saturday and stood in 'very poor' category as surface-level winds helped in dispersal of pollutants. It is likely to deteriorate on Sunday.

Delhi's air quality index stood at 324 micrograms per cubic metres at noon. On Friday, it was 357 micrograms per cubic metre and 425, 433, 418, micrograms per cubic metre the previous days.

According to the Central Pollution Control Board (CPCB), the pollution monitoring station in North-West Delhi's Jahangirpuri area logged severe air quality index reading at 404 micrograms per cubic metre, while 27 others across the city showed the AQI in 'very poor' category.

"The air quality has improved to middle-end of very poor category as forecasted. Good surface winds helped to disperse accumulated pollutants," said the System of Air Quality and Weather Forecasting and Research of Ministry of Earth Sciences.

The surface winds are likely to slow down for a shorter period on Sunday and marginal deterioration in air quality is forecast, the weather forecasting agency said, adding that it will again improve on December 28 and 29.

Delhi's neighbouring regions - Ghaziabad, Greater Noida and Noida recorded 'very poor' quality of air, leaving aside Gurugram and Faridabad which have slightly better AQI. Ghaziabad and Greater Noida have the most polluted amongst all at 352 and 335 micrograms per cubic metre.

SAFAR has issued a stringent warning, asking sensitive groups of people to avoid all physical activity outdoors and move activities indoors. If asthmatic, keep relief medicine handy.

Meanwhile, the India Meteorological Department stated that the cold conditions have persisted in the national capital as the minimum temperature remained below 5 degrees Celsius for the fourth consecutive day.

The Safdarjung Observatory, which provides representative data for the city, recorded a minimum of 4.4 degrees Celsius.