It is important to also remember that the Aryans were a linguistic group and their classification as a racial group happened under British rule. What was a slow migration was transformed into an invasion, and with this in mind, the British were quick to establish themselves in this apparent tradition of invasion.

Scientific racism was a huge thing during colonial rule, and much of the same things applied to slaves in the antebellum south were also applied to Indians like skull size. asrafael already mentioned the Criminal Tribes Act, but on a social level, British and Indian were considered separate even if they were upper caste. Maharajahs weren't allowed to enter white only clubs, and wealthy Indians were still not considered British.... Obviously this would have huge consequences as the nationalist movement was led by these disaffected people.