New Delhi, Dec 17 (IANS): Delhi's minimum temperature was on Monday recorded at 6.2 degrees Celsius, two notches below the season's average and it is expected to drop further by one or two degrees, said Met officials.

"There will be shallow fog on Tuesday morning, followed by smoke or haze with a maximum and minimum temperature of 23 and 5 degrees Celsius, respectively," an India Meteorological Department (IMD) official told IANS.

In terms of pollution, Delhi's air quality along with the temperature also dropped to "very poor" category on Monday, after days of "poor" yet improved air quality. The Air Quality Index (AQI) stood at 337.

"Overall air quality slipped to 'very poor' on Monday and is predicted to deteriorate further due to declining wind speed (from 4.7 km per hour to 2.7 km per hour)," System of Air Quality and Weather Forecasting and Research (SAFAR) said in its daily pollution analysis.

The agency further said that the AQI is going to remain in the "very poor" category for the next three days "with incremental changes".

Humidity, another factor unfavourable for the pollutants to disperse, also remained high on Monday with maximum touching 97 per cent and the minimum going down to 49 per cent.

In the National Capital Region (NCR), Faridabad at 304 and Noida at 334 also slipped into the "very poor" zone in terms of AQI. Ghaziabad at 378 and Greater Noida at 385 remained have been "very poor" since, Sunday while Gurugram, surprisingly, had a moderate AQI of 136.

As per the data of the Central Pollution Control Board (CPCB), the average concentration of PM2.5 and PM10 in Delhi at 7 p.m were 175 and 307 microgrammes per cubic metres, respectively. Across NCR, it was between 169 and 298 units, respectively.