The centre has written to the West Bengal government to take steps to control the rise in number of COVID-19 cases in Kolkata.<br />''<br />''Kolkata has reported almost 27 per cent increase in positivity rate in the past week, from 5.6 per cent in the week ending October 14 to 7.1 per cent in the week ending October 21.<br />''<br />''Union Health Secretary Rajesh Bhushan recently wrote to West Bengal health secretary Narayan Swaroop Nigam saying that Kolkata is one of the certain districts in the country that have started showing a worrying trend in daily new cases and positivity rate in recent weeks. Mr Bhushan wrote that it is crucial to emphasize the importance of Covid safety activities in order to maintain the collective gains made in the battle against the pandemic so far. Mr Bhusan noted that Bengal has recorded 20,936 new cases and 343 new deaths in the last 30 days which accounts for 3.4 per cent of India's new cases and 4.7 per cent of new deaths in the last 30 days.  <br />''<br />''<span style="color: #222222;">Bengal recorded 806 new Covid cases yesterday, out of which 248 were reported from Kolkata</span><span style="font-weight: bold;">.</span><br />