Skeptical about this number because India vs Pak premier match only touched 18 million, which is a lot actually but doesn't look juicy when compared to Aus vs Ire.
I was watching it live on Hotstar and they usually display the viewer numbers. It is not just the Australia vs Ireland match. I witnessed viewership crossing the 10 million mark in a number of other matches as well (many of them not involving India). It proves that Indian fans are interested in the other teams as well and there is no requirement that for matches to be viewed by a large number of people in India they should involve the national team. BTW, today is a working day and the viewership right now is ~12 million.