I checked to see how large the Indic Wikipedias are, and the Tamil project is the largest at #60, while Hindi is #62, Bangla #63. (Urdu is #54, if you count it among them.)
Now, those are further down in the list than I would've expected, but I suppose that the answer is that many Indians are contributing to English Wikipedia in the first place, due to greater exposure and fluency in that country.
There is certainly extensive coverage of Bollywood, cricket, and other topics of great appeal to Indians at home and abroad.
https://meta.wikimedia.org/wiki/List_of_Wikipedias
Now, those are further down in the list than I would've expected, but I suppose that the answer is that many Indians are contributing to English Wikipedia in the first place, due to greater exposure and fluency in that country.
There is certainly extensive coverage of Bollywood, cricket, and other topics of great appeal to Indians at home and abroad.