New Delhi, Dec 27 : Dense to very dense fog is likely to continue over many parts of Haryana, Chandigarh, Delhi and eest Uttar Pradesh and in isolated pockets over north Rajasthan during next 24 hours, the India Metrological Department said on Tuesday. The IMD said that the intensity and spread likely to reduce thereafter, but dense Fog in isolated pockets likely to continue over the above region during subsequent 3-4 days. The minimum temperatures were recorded in the range of 3-7 degress Celsius over many parts of Punjab, Haryana, Chandigarh, Delhi, Rajasthan, west Uttar Pradesh and adjoining northwest Madhya Pradesh. The lowest minimum temperature of 0.5 degrees Celsius was reported at Churu in west Rajasthan. According to the Metrological Department, the cold wave to severe cold wave conditions prevailed in many pockets over Himachal Pradesh and in isolated pockets over Haryana and north Rajasthan on Tuesday. While cold to severe cold conditions are very likely in isolated pockets over north Rajasthan during next two days, cold wave conditions will prevail in isolated pockets over Punjab, Haryana, Chandigarh, and Delhi during next 24 hours, it said. A cold day is when the minimum temperature is less than or equal to 10 degrees Celsius below the average and the maximum temperature is at least 4.5 degrees below the average. A severe cold day is when the maximum is 6.5 degrees or more below average, and a severe cold wave is when the minimum temperature dips to two degrees Celsius or the departure from the average is more than 6.4 degrees Celsius. "Cold day/severe cold day conditions very likely in some parts over Punjab, Haryana, Chandigarh, Delhi on December 27 and over west Uttar Pradesh on December 27 and 28," the IMD said. /IANS