When the census stopped recording caste details after 1931, the reason was the tendency among the underprivileged to register themselves as members of higher social orders. Caste detailing may reappear in the current census, but the concern this time is quite the opposite—in a country replete with reservations for backward castes, there are strong incentives for people to register themselves as members of such categories.
All this is well known to our policymakers. Nonetheless, the inherent political capital in caste-based politics means the government has enough motive to accede to the demand for caste details.
However, there could be unintended consequences implied in such a move. The census is primarily an enumerator—an objective chronicler of Indian life. With a caste element added, it may well become a political tool for redistributive policies in a country that is already burdened by them, not to mention the misguided social and political mobilization that distorted data on castes could give rise to.