Kolkata, Oct 31 : Prices of onions in Kolkata have doubled in the past one week to be sold at Rs 75-80 a kilogram in the retail markets. Just a week back, the rates were between Rs 35 and Rs 40 per kilogram. The recent surge in prices has left even the members of the task force of the state government constituted for keeping the prices of essential commodities in the retail market, perplexed. Probably, said a member of the task forces, the double-factor of lesser supply and sudden spurt in the demand for the product during the last two weeks because of the festive season might be the reason for this sudden doubling of price in the retail markets. The task force members apprehend that while there is not much possibility of the softening of the price of onion during the current month, apprehensions of further northward movement in price of the product are there because of the forthcoming festivals of Kali Puja, Diwali and Bhai Fota (Bhai Dooj) festivals. Meanwhile, the state government sources said that there might be an attempt on part of the state government to keep the prices of onions in the retail markets under control through the release of the state government's own stock of the product. The task force members and the sleuths of the Enforcement Branch (EB) of the state police have been asked to keep a close watch on the retails markets to prevent any attempt to artificially jack up the prices of onions as well as other vegetables there. /IANS