There's a really big literary fiction book coming out that is set partially in Guyana next year. I think it got a seven figure advance or something.
Interesting. I'd love to know more.
I'm chiming in late here. I think, as other have said, that there are probably several reasons for sales being different. Having said that, I do think that white people, generally speaking, have problems dealing with POC characters. I say that as a white person and a former literature professor, and a mother of white children who tries to teach her kids to understand what it might be like for other people to read books that have characters that, by in large, feature characters that are chiefly colored in one skin tone, and that skin tone is different from their own.
This came up because my son is reading Percy Jackson and evidently there is a character depicted as white in a book and in the movie adaptation he is black. I explained a few reasons why this might be to my son. You literally have to force people who are white to look at these things. It is not something they can see without help most of the time. I think many of them are uncomfortable with it, and this might keep them from buying a book. The open minded ones, of course, would be interested. But as we know, not everyone is open-minded. And that is not even taking into account the ones who are not only open-minded, but who are flat-out racist but don't admit it.
When white people don't get it and complain about black people whining, I sometimes ask them to imagine if all the books available, all the books they read while growing up, had exclusively black or brown characters, with the only white characters ever appearing in minor roles. Just imagine it, as a white person. Wouldn't it feel weird? Wouldn't you want, as a white person in a mostly white society, want a BIT of diversity? Would that be whining?
As far as why India might be more salable . . . that I don't know, unless there is a higher reading population among the East Indian American public? I would imagine white Americans are just as bad about East Indians as they are about African Americans.
We're talking more about UK readers here. The UK has a long and colourful history with India. India was "the jewel in the crown". The British have this romantic idea about India, opulence, maharajahs, princesses on elephants, and all that -- and OTOH, misery, oppression, women in purdah, arranged marriage etc -- it all sounds very exotic and apparently readers are drawn to the "exotic". Not to mention, in more reacent years, spirituality, yoga, etc. Just about every book I read recently set in India and written by non_Indians has some kind of "guru" in it. Usually a lot of imagined nonsense.