The problem is that even though there probably are 300 million muslims in India, they are spread thin. Except Kashmir, which is a occupied territory, there is not a single state where muslims are majority.
Hindus dont vote for muslim candidates. muslims OTOH vote for both muslim or hinfu camdidates. If forexample muslims had concetrated their voted on muslim candidtes, like hindus do for hindu candidates, then there would be more muslim MP’s.
Anyway, its a grim paradox, India calling itself largest «democracy in the world», yet 25% of its population practically have no political representation.