Kolkata, Jan 1 : Considering the rapid increase of Covid cases in the city, the West Bengal government and the Kolkata Municipal Corporation have decided to impose the micro-containment zones in the city where the spread of virus is high. Presently, there are 17 places in the city where the concentration of the disease is high and the administration has decided to impose containment zones in these areas. "Most of the people who are getting infected are asymptomatic. According to the Health Department, 80 per cent of the patients are asymptomatic. There are symptoms among 20 per cent of the patients of which 3 per cent have to be hospitalised," Mayor of Kolkata Municipal Corporation Firhad Hakim said. "We are thinking of imposing a micro-containment policy where the concentration of the disease is more than five. We have identified some areas and will impose restrictions soon," he added. Kolkata's tally of new Covid-19 infections more than doubled in 24 hours as the metropolis reported 1,090 cases on Thursday, as per the state Health Department. The city reported 540 new cases on Wednesday, it said. West Bengal registered more than 2,000 cases after nearly six months, at 2,128 new infections. It was nearly double the cases reported on Wednesday when 1,089 infections were detected, and more than four times that reported on last Thursday -- 516. The state's positivity rate jumped to 5.47 per cent, from 2.84 per cent on Wednesday. West Bengal has so far reported 16,35,034 Covid-19 cases. The state also registered 12 more deaths, taking the toll to 19,757. Four of the latest deaths happened in Kolkata, two each in North 24 Parganas, Hooghly and Darjeeling, and one each in South 24 Parganas and Paschim Medinipur. In the last 24 hours, 1,067 people recovered from the disease. So far, 16,06,501 people have been cured of Covid-19 in the state. There are 8,776 active cases in West Bengal at present. /IANS