The animosity is kind of blurring now, at least in South India. We have Bangalore and Hyderabad which are excellent examples of a super-heterogeneous population, running as one big machine. Chennai's trying, but hasn't gotten there yet. ;)
The population is heterogeneous, but there's still a fair amount of distrust and alienation between north and south Indians. However, I agree that that's still a step forward from the "animosity" of the previous generation.
Fair enough. "Animosity" might have been the wrong word. I didn't mean to imply that there hadn't been any progress on this front.