Very dense fog also enveloped the city bringing down the visibility to less than 50 metres in the morning.
Indian Meteorological Department (IMD) station director at Patna, A K Sen told PTI, "An advection fog having a radius of 30 kilometres was noticed over Patna just after sunrise. It brought down the day temperature 9 degrees below the normal. The departure in minimum temperature was also 4 degrees from the normal."
Advection fog is formed by the slow passage of relatively warm, moist, stable air over a colder wet surface.
Muzaffarpur in north Bihar experienced maximum and minimum temperatures of 18 degree C and 8.8 degree C respectively. In Supaul it was 19.9 and 7.1 degrees, while at Chapra it was recorded at 16.1 degree and 5.7 degrees. Apart from Patna, very dense fog was also seen at Purnia on the northeast corner of the state.
Dense fog hit transport services across the state. Dozens of long distance trains were running late from three to 15 hours. Flights at the Patna airport were rescheduled as very low visibility hampered landing of aircraft.
Meanwhile, the state government has ordered burning of bonfires at important public places so that the poor could escape the cold.
