The caste system divides society in the Indian subcontinent into mutually exclusive, hereditary groups called castes, ranked by ritual status. Traditionally, South Asians believed that a man’s social capacities were known from the caste into which he was born, and his caste prescribed the occupations that he could enter. The most distinctive features of caste ideology are the emphasis on the innately unclean state of the lowest-ranked castes, formerly known as untouchables, and the strict exclusiveness of the so-called clean castes in relation to marriage. There is virtually no mobility of individuals across different caste groups. Nothing quite like the caste system has evolved in other parts of the world.

When India became independent in 1947, a political goal was to create a “modern,” casteless India. ...