New Delhi, Apr 20 (IANS): The Centre on Tuesday wrote to five states with higher contribution to country's Covid caseload and a higher positivity rate.

"These are few states which are reporting a higher contribution to India's caseload and a higher positivity rate. The Centre advised all states and UTs to follow a risk assessment based approach on the opening of economic and social activities without losing the gains made so far in the fight against the pandemic," said Rajesh Bhushan, Union Health Secretary in the letter.

These five states include Haryana, Uttar Pradesh, Mizoram, Maharashtra and Delhi.

The Union Health Ministry has advised all states to continue monitoring of spread of infection and undertake required steps for prompt and effective management of Covid-19.

It has advised to continue five fold strategy of "test-track-treat-vaccination and adherence to Covid-appropriate behaviour", with particular emphasis on wearing masks in crowded places.

"It is essential that state must maintain a strict watch and take preemptive action if required in any areas of concern to control any emerging spread of the infection," said Bhushan in the letter.

Regular monitoring and prompt follow up action in emerging areas of concern is crucial, he added.