"Mr. Beverley’s opinion, that even a low-caste Hindu, on his conversion to Islam, attains to a position of equality with the generality of Musalmans, simply betrays his ignorance of the customs of the Musalmans. From a religious point of view, of course, all Musalmans stand on a footing of equality. But according to usage and customs the social position and the family rank of a man do not become altered by the change of religion. .In fact the social position of a Musalman convert exactly corresponds to the station he held previous to his conversion, and he can associate with only such Musalmans as belong to the same station as he himself ; a low-caste person on his embracing Islam, is not allowed to hold familiar intercourse or claim equality with high-born Musalmans, nor can a Hindu of superior caste, upon his conversion to Islam, marry into a respectable Musalman family. Rigid and scrupulous regard has ever been paid by the Musalmans to social position and family dignity."
January 1, 1970
https://en.wikiquote.org/wiki/Caste_system_among_South_Asian_Muslims