The Union Health Ministry on Sunday listed parameters such as active COVID-19 cases, doubling and fatality rates and cases per lakh population, for the states and UTs to follow while categorising areas into red, orange or green zones.
It also issued guidelines for delineation of coronavirus containment and buffer zones and outlined the actions that have to be implemented in those areas to break the chain of transmission.
In a letter to the states and Union Territories, Health Secretary Preeti Sudan said states may categorise districts or municipal corporations into hotspots, red, orange and green zones.
They, however, may also choose to categorise sub-division, ward or any other appropriate administrative unit into the colour-coded zones after detailed analysis at their end, duly taking into consideration the geographical spread of cases, contacts and their zone of influence in terms of disease spread, the ministry said.
This comes after the Home Ministry issued guidelines for the fourth phase of the nationwide lockdown, giving power to the states and Union Territories to delineate red, green and orange zones as per the COVID-19 situation.
In her letter, Sudan said demarcation of the zones would be based on total active cases, 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