The Centre on Sunday said that states can designate their respective areas into red, orange and green zones as a measure to curb the coronavirus outbreak.
The Centre, however, also listed out parameters that had to be taken into consideration before doing so.
In a letter to all States and Union Territories, Union Health Secretary Preeti Sudan gave the detailed plan that must be followed for districts or municipal corporations to be divided into red, orange or green zones.
As per the parameters, the demarcation of zones would be based on total active cases, active cases per lakh population, doubling rate calculated over a seven day period, case fatality rate, testing ratio (number of tests per lakh population) and sample positivity rate.
The benchmarks or thresholds for critical and desirable levels for total active cases would be more than 200 and zero or no reported case in the last 21 days, respectively.
For active cases per lakh population, the critical threshold would be when more than 15, while for doubling rate calculated over a seven-day period, the critical level would be less than 14 days and desirable when more than 28 days.
For case fatality rate, more than six per cent would be considered critical and less than one per cent would be desirable.
The critical threshold for testing ratio (number of tests per lakh population) would be less than 65 while the desirable level would be more than 200, according to the letter.
Sample positivity rate would be considered critical if it’s more than six per cent while less than two per cent is desirable.
Meanwhile, the Centre on Sunday extended the fourth phase of lockdown from May 18 to May 31.