The delta variant, considered more contagious than chickenpox, has now pushed up the R-naught -the average number of people who will contract the disease from an infected person - above one for India from 0.93 a month ago.
The R-value is tool epidemiologists and policymakers use to check if cases are growing faster or shrinking quickly. The reproduction factor in India is 1.01.
"This means one person is infecting more than one person," explained Vellore-based senior virologist Dr T Jacob John. In March, as cases went up rapidly the R-value was around 1.4 but by May, when overall cases began to fall, it dropped to around 0.7.
While rising R0 is a cause for worry, epidemiologists say they don't red zone a state or district merely because the R-value is going up.
"A combination of epidemiological factors including infection growth rate, an increasing number of deaths and hospital occupancy rate explain the risk," said National Institute of Epidemiology director Dr Manoj Murhekar.
At least 10 states have an R-value higher than the national average of 1.01, and Delhi and Maharashtra (both at 1.01) have inched closer to match the national average.
Among states, Madhya Pradesh (1.31) has the highest R-value in the country followed by Himachal Pradesh (1.30) and Nagaland (1.09). Across India, by August 5, of the eight states that reported over a thousand cases, the R number was higher than one in five states.
Kerala, which is reporting more than 20,000 cases a day, has a RO of 1.06. The number is above 1 for Karnataka, Andhra Pradesh and Maharashtra as well