Patiala, Jan. 8 -- With biting chill gripping Punjab, the India Meteorological Department (IMD) has issued an orange an alert for cold wave and dense to very dense fog across large parts of the state for the next two days. An orange alert is the second-highest warning in IMD's four-colour system, advising residents to be prepared. As per IMD, a "dense fog" day is declared when visibility drops between 50 and 200 metres. Visibility below 50 metres is classified as "very dense fog", while readings between 200 and 500 metres fall under "moderate fog". The persistent fog cover, which blocks the sun, is leading to a noticeable drop in mercury, with Fazilka recording the lowest day temperature of 10degC on Wednesday. Cities such as Amritsar, Ludhiana, Patiala and Chandigarh also witnessed dense to very dense fog during the morning and evening hours. "As compared to yesterday, there is a fall of 1.7degC in the state's average maximum temperature over the past 24 hours. It is markedly below normal by 6.1degC in the state," read the IMD daily bulletin. IMD has warned that cold wave conditions are likely to persist in various districts, including Fazilka, Muktsar, Bathinda and Mansa, while cold day conditions have been predicted for SBS Nagar, Rupnagar, Patiala and Mohali. According to the IMD, cold day conditions are defined based on the maximum temperature, while a cold wave is determined by the minimum temperature. In this region, a day is classified as a cold day when the maximum temperature is 4.5 to 6.4degC below normal and the minimum temperature falls below 10degC. A cold wave is declared when the minimum temperature drops 4.5 to 6.4degC below normal. "There is no immediate relief in sight, and residents should remain alert and follow advisories until weather conditions improve. Wind chill factor is leading to bone-chilling cold in the evening," said an IMD official. IMD has cautioned people against prolonged exposure to cold, with health experts warning that cold wave conditions can increase the risk of ailments such as flu, cold, cough, nosebleeds and aggravation of respiratory diseases like asthma and bronchitis. Shivering should not be ignored as it is an early sign of the body losing heat. "People, especially children, the elderly and those with existing health conditions, are advised to stay indoors, wear layered warm clothing, consume warm fluids and avoid early morning outings," reads the IMD advisory. "Dense to very dense fog is also expected to continue over most parts of the state for the next couple of days, impacting road, rail and air traffic," said an IMD official. Motorists have been urged to exercise caution, use fog lights and maintain safe speeds due to low visibility....