UK estimated total of University students: just under 2 million (BBC figures, 2009) and shrinking slowly
India estimated total of University students (or at least places): just over 12 million, government policy to increase by factor 2 over by 2025 (BBC 2011 article)
I think you could discount heavily to something close to local wage rates and still make a handsome profit in India, especially with electronic distribution reducing the distribution costs.
Does anyone else remember/use the Indian editions? I remember Tata/McGraw Hill having a series of Indian printed editions of popular texts. Local production and typesetting, lower price. Some of them even made it to the UK in the 1980s.