Winter in Delhi
© Gajendra Yada
The capital Tuesday recorded its lowest maximum temperature in December in the past 22 years, with 12.2 degrees being the highest reading of mercury, India Meteorological Department officials said.

This is the lowest the temperature has dipped to since 28 December 1997, officials said, when it was 11.3 degrees Celsius.

Kuldeep Srivastava, scientist at IMD, said the temperature was also the second lowest since 1992.

He added, "It was caused due to strong and cold north westerly winds from western Himalayan region and a layer of low clouds stopping the sunlight from reaching the surface of the earth."

The difference between the maximum and minimum temperature Tuesday was also very low with the minimum temperature recorded at 10.4 degrees Celsius.

Experts have said the condition is likely to persist on Wednesday as well, after which the temperature would increase.

On Monday, the maximum temperature in the city was 12.9 degrees Celsius, lowest since December 2003.

As per an IMD official, 28 December 1973 has so far been the day which holds the record for having the lowest maximum temperature, at 11.2 degrees Celsius.

The cloud cover over Delhi was said to be around 500 to 1,000 metres above ground, which is considered "very low," and is credited with causing the dip in temperature.

The IMD has forecast dense fog in isolated parts of the city on Wednesday morning.

Meanwhile, Delhi's average air quality index (AQI) was in the 'moderate' category Tuesday with a reading of 168, as per the Central Pollution Control Board.

Among NCR cities, Gurgaon's AQI was 106 in the moderate range, while Ghaziabad's was 238 and Noida's 211 in the 'poor' range.

A report by the Centre-run System of Air Quality and Weather Forecasting and Research Tuesday said high surface level wind speed, which help in dispersion of pollutants, are forecast to continue until Wednesday night. The report added, "A decrease in wind speed is forecast for December 19 and therefore AQI is likely to deteriorate to the higher end of 'poor' or the lower end of 'very poor' category. On December 20, the AQI may further deteriorate to the 'very poor' category."