New Delhi, Dec 13 (IANS): The air quality in Delhi on Thursday registered an improvement from 'poor' in the morning to 'moderate' in the evening due to increased wind speed and Wednesday night's rainfall.

The Air Quality Index (AQI) at 4 p.m. was recorded at 194 (moderate) against Wednesday's 392 (very poor), on a scale of 0 to 500.

In the national capital region (NCR), Gurugram, Noida and Ghaziabad also recorded 'moderate' levels of air pollution, between 101 and 200 on a scale of 0 to 500.

Only Faridabad and Greater Noida in the NCR fared 'poor' with AQI at 220 and 234, respectively.

"Wednesday night's rainfall along with moderate winds were sufficient enough to wash away air pollutants significantly," the System of Air Quality and Weather Forecasting and Research (SAFAR) said in its forecast.

However, the agency said, the respite from 'severe' levels of pollution might not last long as the humidity is very high and the temperature is likely to be cool.

"Both factors are unfavourable and if winds slow down, which is expected by Friday evening, pollution may start building up faster and may push the AQI to very poor level by the weekend," it said.

As per the data of the Central Pollution Control Board (CPCB), the average concentration of PM2.5 and PM10 in Delhi at 6 p.m. was 93 and 160 microgrammes per cubic metres. Across NCR, it was 94 and 160 units, respectively.

Due to meteorological conditions, Monday and Tuesday in Delhi-NCR were the worst breathing days of the month with air quality levels reaching 'severe' category, between 401-500.

Delhi's minimum temperature on Thursday morning was recorded at 11.2 degree Celsius, three notches above the season's average. The India Meteorological Department (IMD), however, has forecast a gradual drop in the minimum temperature from December 14.