A piercing cold wave swept across the hilly states in north India and blanket of fog covered the plains, hampering the movement of air, rail and road traffic yesterday.<br/>In Delhi, as many as 350 planes flying into and out of Delhi were delayed, diverted or cancelled as the season's "worst" fog reduced visibility to 50 metres at the Indira Gandhi International Airport. <br/>The mercury continued its downward spiral in Jammu and Kashmir. Leh in the Ladakh region braved the coldest night so far this year at minus 15.2 degrees Celsius.<br/>Srinagar city recorded a minimum of minus 3.6 degrees Celsius. Strong icy winds swept Shimla and surrounding areas and the sky remained heavily overcast, raising hopes of a snowy<br/>start to the New Year.<br/><br/>The weather in Uttar Pradesh remained mainly dry, while dense to very dense fog occurred at many places. Day temperatures fell appreciably in Varanasi, Allahabad, Kanpur, Jhansi and Agra.<br/>In Bihar, cold and fog has thrown normal life out of gear. Rail, road and air traffic has been badly affected throughout the state due to low visibility.<br/><br/>Over one dozen people were reported died due to cold in Patna, Muzaffarpur, Samastipur, Sheohar and Darbhanga districts of the state. Several trains including Rajdhani express trains either originating or passing through Bihar are running 10 to 15 hours behind the scheduled time. With frequent cancellation and inordinate delay of flights Patna airport has literally turned into a railway station for last three days. Hundred of passengers kept waiting at the airport.The minimum temperature dropped by 1 to 2 degrees Celsius at most places in Rajasthan due to northwesterly winds. Fatehpur Shekhawati shivered at 0.5 degrees Celsius. Mount Abu had a low of 3 degrees Celsius.Cold wave conditions prevailed at many places in Punjab and Haryana. Adampur in Punjab recorded 2.3 degrees Celsius. <br/><br/>Meanwhile, India Meteorological Department has predicted that dense fog condition is likely to continue over Uttar Pradesh and Bihar and some parts of Haryana, Punjab and West Bengal in the next two to three days. Talking to AIR, IMD scientist, Charan Singh also forecast cold wave conditions in Punjab, Haryana and Rajasthan in next couple of days.<br/><br/>