There's a bit more to being well educated than basic literacy though, and it's only among the young that literacy almost reaches 90%

Your link also notes that there are 255 million illiterate people in India, which is around the total population of the world's fourth most populous country.

Googling India literacy rate finds a source which says 75%. Maybe my gut experience is wrong because I live in an urban city in India, but I would be pretty impressed by 90%.