PATNA, Dec. 27 -- A biting cold wave continued to sweep across Bihar on Friday, with temperatures plunging to single digits in several districts and thick fog reducing visibility to near zero in many areas. The India Meteorological Department (IMD) has sounded an orange alert for dense to very dense fog in multiple districts, coupled with cold day conditions that have disrupted daily life and transportation. Residents woke up to another foggy morning, with visibility dropping as low as 100 meters in places like Patna, Gaya and Valmiki Nagar. The chill was particularly severe in southern and northern parts of the state, where minimum temperatures hovered between 7.4degC and 9degC. Aurangabad and Sabour in Bhagalpur recorded the lowest at 7.4degC, while Gaya registered 7.6degC. Other cold spots included Bhagalpur and Sheikhpura at 8.9degC each, Valmiki Nagar in West Champaran and Dehri at 9degC, Jehanabad at 9.3degC and Saharsa at 9.5degC, according to IMD data. The orange alert covers districts such as East and West Champaran, Gopalganj, Siwan, Saran, Sitamarhi, Sheohar, Muzaffarpur, Vaishali, Patna, Bhojpur, Buxar, Kaimur, Rohtas, Aurangabad, Arwal and Jehanabad. Officials have urged caution, especially for motorists and vulnerable groups like children and the elderly. "The fog is not just making mornings gloomy; it's hitting road, rail, and possibly air traffic hard," said a senior IMD official....