Union Health Secretary Rajesh Bhushan has written to all the states and union territories asking them to curb crowding in the wake of New Year celebrations and keep a strict vigil on all events that could be a potential superspreader, the ministry said on Wednesday.

A total of 107 samples have undergone genome sequencing till now, and as many as 20 people who have returned from the UK to India have tested positive for the new 'more infectious' Coronavirus strain. On Tuesday, six patients were found to be infected with the mutant virus. These were the first cases to be reported by the country.