Census Moment UPSC relevant
The census moment is the precise instant — 00:00 hrs of the reference date — that separates who is counted from who is not.
PIB's Census 2027 backgrounder notes that the 'Census Moment helps the enumerators to decide which persons are to be included in the census.' In practice, a baby born after the census moment is not counted, while a person alive at the moment but who dies before the enumerator's later visit is still counted. For Census 2027 the census moment is 00:00 hrs, March 1, 2027 (00:00 hrs, October 1, 2026 in the snow-bound areas of Ladakh, J&K, Himachal Pradesh and Uttarakhand).
The revisional round exists precisely to update the field count to this moment.