Northern India is bracing for severe cold, dense fog, and cold day conditions through the New Year, according to the India Meteorological Department (IMD). The harsh weather is attributed to a confluence of atmospheric forces, including a polar vortex, an Arctic blast, and a western disturbance. These phenomena are expected to cause persistent fog over Punjab, Haryana, and Uttar Pradesh, with cold conditions also affecting Bihar. Heavy rain and snowfall are forecast for Jammu and Kashmir and Ladakh.