Parameters laid down by the Union Health Ministry such as active COVID-19 cases, doubling and fatality rates and cases per lakh population have to be taken into consideration by states and union territories while categorising areas into red, orange or green zones.
The ministry also issued guidelines for delineation of containment and buffer zones and outlined actions that have to be implemented in those areas to break the chain of transmission of the disease.
In a letter to states and union territories, Union 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 the disease spread, the letter said.