The country confirmed the last million cases in just 20 days, faster than the US or Brazil which have higher numbers.
Testing has been expanded considerably in India in recent weeks but the situation varies across states.
Spurred by a low death rate, the nation continues to reopen even as new hotspots drive the surge in cases. But some states have imposed restrictions.
The recent measures include local, intermittent lockdowns, sometimes limiting activity in specific cities or districts.
India is now the third country to cross the two million mark. It reported 62,170 cases in the past 24 hours, taking its total tally up to 2,025,409.
The country has reported around 40,700 deaths so far. While that is the world's fifth-biggest total, experts say it is not very high given the country's population of 1.3 billion.
The government, however, has been accused of undercounting COVID-19 deaths due to a variety of reasons - from lags in reporting to rules on how India determines if a death was caused by the virus.