Hmm interesting, lets assume you're correct for a moment, North Indians tend to be of skull structure, while the ones in the south tend to be of Australoid skull structure (more similar to Australian Aboriginal people) , the people close to you borders with China and Nepal in North East tend to be of Mongoloid skull structure (more simmilar to people of South East Asia, East Russia , indigenous people of parts of pacific )
Now these are 3 types of human beings, with not only different races and distinct bloodline but completely different skeletons and skulls, how do you define that race which belongs to India then !!!