The Crisil note said due to the aggressive play by the telcos, which started giving the fast 4G connectivity at low rates, the number of subscribers had stagnated at 19 million since 2016.
Till now, the lower speed 4G served the purpose for people due to affordable smartphones, it noted.
"But now, subscriptions to fixed broadband, especially in the urban areas, have surged because millions are working from home...," it said.
Data usage has darted up 25-30 per cent since the lockdown began on March 25, the note said.
"Lockdown has come as a godsend to the fixed broadband sector," it said, adding that on the flip side, data speeds have gone down as more subscribers are using the services.
It said that the benefits are all set to continue in the medium term as well, as there is a likelihood of a hike in prices to be done by telcos as well.
The telcos' price hike will help sustain some of the uptick in fixed broadband usage because its price differential with mobile data will reduce, it explained.
Fixed broadband penetration in India is among the lowest in the world at only 6 per cent as compared with 55 per cent in China, 70 per cent in Eurozone and 80 per cent in Japan, the note mentioned.