New Delhi, Dec 14 (IANS): Delhi will witness one of the coldest days this winter season with the minimum temperature dipping to 5 degrees Celsius on December 20, data from the India Meteorological Department (IMD) revealed on Tuesday.

According to the IMD, the minimum temperature will settle at 7 degrees Celsius till Thursday, 6 degrees on Saturday and Sunday, and 5 degrees on December 20.

The maximum temperature too, will drop to 21 degrees Celsius with foggy mornings throughout the week.

The maximum temperature for Tuesday in the national capital has been pegged at 23 degrees Celsius, while the relative humidity at 8.30 a.m. was recorded at 95 per cent.

After a day of slight improvement, Delhi-NCR's Air Quality Index (AQI) again deteriorated to the 'very poor' category.

The AQI at 9 a.m. was recorded at 335, as per the System of Air Quality and Weather Forecasting And Research's (SAFAR) estimates.

The levels of PM 10 and PM 2.5 pollutants in the air were recorded at 274 and 165 in the 'poor' and 'very poor' categories, respectively.

"The air quality over Delhi-NCT is likely to remain in the very poor category on December 14 and 15. The air quality is likely to improve and remain in the lower end of the very poor to poor category on December 16. The air quality is likely to improve significantly from December 16 onwards due to relatively stronger wind," said the air quality and weather bulletin for Delhi-NCR.