Northern and central India are experiencing a severe cold wave, with temperatures dropping significantly and forecasts indicating continued harsh conditions through mid-January. Delhi has recorded its first cold day of the season, and dense fog is disrupting visibility, impacting road, rail, and air travel across the region. Hill states like Himachal Pradesh and Jammu and Kashmir are reporting sub-zero temperatures, with Kukumseri reaching minus 9.2 degrees Celsius. Meanwhile, southern India is under a rain alert.