They cannot raise the “caste level” by the pigmentation of the offspring. In fact, marrying a foreigner is the quickest way to lower oneself in the racist caste heirarcy.
It is for this reason that Anglo-Indians were accorded special protection by the Indian constitution.
I am thinking of how it is among people I know. Both families’ Indian sides are based in Goa which might make a difference. Both of the men, one Irish and one Carolinian intend to retire to Goa to be, at least in part, near their (wives’) families.