The demand for a caste-based census has intensified, with more parties coming out in favour of comprehensive data on different castes. The practice of a caste-based census was discontinued pre-independence, as the legislators feared the "divisive impact of the exercise". Data on Scheduled Castes and Scheduled Tribes has been a part of census since 1951, and there has been reliance on estimates for caste data till now. The BJP govt has turned down the demand, saying caste-based census will be "an enormous and costly exercise". According to Mandal Commission estimates, Other Backward Classes or OBCs comprise over 50 per cent of the population. In the backdrop of calls for review of 50 per cent reservation cap, we decode what's driving the debate behind caste-based census?