I remember the imdb-ratings on movies from India were also absurdly high, I brushed it off as a cultural thing back then; but unfortunately [0] the rigging seems to be norm on imdb across the board (not limited to India).
After Amazon bought IMDB it became more about advertising for movies and less about being a database. Same thing as when Warner Bros and Universal Studios (via its parent Comcast) bought RottenTomatoes. Now everything brags about it's RT rating when it's coming from 2 movie studios...
I do really like the "X-ray" feature in Amazon Prime, which I assume is partially powered by IMDB. I miss it when using other services like HBOMax, Netflix, etc.
RT at least still has viewer ratings. You predictably can't sort by them but it's at least an indicator if the reviewer and viewer score are on completely different heights.
And you've got trakt.tv now too, not sure if anyone owns that
Indian fake ratings are a big thing, but from my own experience collecting good ratings, I can attest that keeping fakes out if the system is a big effort, and it cannot be done manually. I implemented a complicated but fair statistical system to keep fake ratings out from my site. But I'm only doing the top 3 film festivals, not all the crap. The manual blacklist is still huge.
In the west the biggest offender is A24 btw.
And to be fair to the Indian movies: The top Indian movies are usually better than the best western movies. But we didn't have top Indian movies for almost over a decade now.
I"m an Austrian film critic, who just watches most good movies.
Since Indian movies rarely make to to western festivals (mostly only Rome), there's not much to compare with. The ones which make it into Cannes are entirely different, and not as the good ones which make it into Rome or dominate the local markets. Berlin has nothing (but Dil Se won there ages ago, still the top Indian movie), Sundance had at least Gangs Of Wasseypur.