De Facto Method UPSC relevant
Under the de facto method, people are counted at the place where they are physically present at the census moment, rather than at their usual home. A pure de facto count must be completed very quickly (ideally in one night) to avoid double counting of travellers.
India follows what demographers call an 'extended de facto' approach: enumerators canvass households over an enumeration period of about three weeks, count people where they normally stay during that period, and then correct the record to the census moment through a revisional round. The houseless population is a true de facto count — enumerated wherever found on a single designated night. Understanding this distinction matters in 2027 because self-enumeration entries must still be reconciled to the March 1, 2027 census moment.