Three things make this notification consequential. First, caste: the last enumeration of all castes was in 1931, so every reservation debate since has argued from estimates rather than counts, and an open-ended caste field will produce a dataset that reshapes those arguments. Second, the identity fields: recording Aadhaar, voter ID, driving licence and passport numbers turns the census into a bridge between population data and administrative databases, which raises both efficiency gains and data-protection questions. Third, the timing: census data drives delimitation of parliamentary and assembly constituencies, the allocation of seats reserved for SCs and STs, and the population figures used in Finance Commission devolution - all of which have been running on 2011 numbers for well over a decade.