New Delhi, Dec 26 (IANS): After four consecutive days of "severe" air pollution, Delhi's air quality improved to "very poor" and according to the weatherman, it is likely to remain in the same zone for the next three days, with dense fog engulfing the city.

"Although the overall air quality will remain in the 'very poor' zone for the next three days, it will improve by a few notches by Thursday as good wind speed prevailing over Delhi and adjoining areas will continue to disperse pollutants," System of Air Quality and Weather Forecasting and Research (SAFAR) said in its daily pollution analysis.

However, the agency said moderate to dense fog conditions will prevail for the next two days over Delhi and surrounding regions and may not allow significant improvement.

"There will be dense fog on Thursday morning, with visibility dropping to 100 metres. However, the fog will soon disperse and the rest of the day will have a clear sky with maximum and minimum temperature hovering around 21 and 4 degrees Celsius, respectively," an India Meteorological Department (IMD) official told IANS.

There will also be cold wave-like conditions at isolated places in Delhi, the official added.

In terms of pollution, Delhi's Air Quality Index (AQI) at 4 p.m on Wednesday was recorded at 384 (very poor), against Tuesday's "severe" air quality of 409.

In the National Capital Region (NCR), Faridabad at 327, Ghaziabad at 398, Greater Noida at 394, Noida at 386 and Gurugram at 310 also fared in the 'very poor' zone.

Across 35 areas in Delhi, where pollution is actively monitored, the average concentration of PM2.5 and PM10 was 230 and 353 microgrammes per cubic meters on Wednesday at 6 p.m.

The same PM2.5 and PM10 concentration across 48 monitoring stations in the NCR was 220 and 341.