Bone-chilling cold continued to sting east and north India on Tuesday with the mercury nosediving to seven-year lowest in Kolkata.West Bengal capital Kolkata recorded a low of 9.9 degree Celsius — the lowest in seven years, while hill station Darjeeling at -1.0 deg C was the coldest in the state.Kolkata had recorded minimum 9.4 deg C on January 6, 2004. A cold wave alert has been sounded in 10 districts in the state. Severe cold conditions continue to prevail in Uttar Pradesh.Agra at minimum 1 deg C was the coldest place in the state. Lucknow recorded a minimum of 1.4 deg C, six notches below normal.Chill intensified in Bihar as north-westerly winds continued to sweep the region, prompting the state government to announce closure of all schools till January 14.Gaya at minimum 3.9 deg C was the coldest in the state. The minimum temperature in state capital Patna settled at 5.5 deg C as against 8.5 deg C recorded on Monday.Low temperature coupled with icy winds made life miserable for the people in Delhi where the minimum temperature settled below the normal level.The minimum temperature was recorded at 4.6 deg C, two degrees below normal for this time of the year. However, there was no dense fog in the city and flight operations were normal at the IGI airport.Punjab, Haryana and Chandigarh on Tuesday got some respite from the biting cold during day due to sunshine at various places. Chandigarh registered a maximum temperature of 17 degree Celsius only four degree below normal whereas minimum temperature was 3.7 degree celsius.Rise in maximum temperature was also registered at Ambala, Hisar, Karnal Ludhiana, Patiala and max temperature at all places was above 17 to 18.5 degree Celsius at all these places. Hisar despite minimum temperature of 2.5 degree Celsius was cozy during day at 18.5 degree Celsius. At most of the places the maximum temperature was 2 to 4 degree below normal but at Amritsar it was 6 degree below normal at 14.4 degree Celsius and night was coldest at minimum temperature of 1.4 degree Celsius. Met department forecasts that ground frost, rain or thundershowers could occur at isolated places in Haryana and Punajb, fog and mist may occur during night and weather will be mainly dry.