Taken from Cheikh Anta Diop Pre Colonial Africa on the Caste system in India.
''It has often been mainatained, without production of any conclusive historical documents, that it was the Aryans themselves who created the caste system after having subjugated the Black Aboriginal Dravidian populace. Had this been the criterion of color should have been at its foundation: there should have been at most three castes, Whites, Blacks and the gamut of Crossbreeds. However , this is not the case and in India also the castes effectively respond to a division of labor without any ETHNIC connotations. ''
He elaborates more on the caste divisions. I'm not a historian and I don't study history as vigorously as some on here but I have never bought into the fantasy that a bunch of White Aryans walked into India and subjugated the Blacks and implemented the Caste system.
Plus the British were in India for 400 years. Thats a long time when you can consider the transformations of Africans in the new world under a similar time span.