A census night is the night immediately before the first day of enumeration. It is the night when homeless persons are usually enumerated.
The census reference period is the time from the zero hour (00:00) of the first enumeration day to the midnight (24:00 hrs) of the last enumeration day. The time of visit by an enumerator for an interview must therefore be within the zero hour of the first day to the midnight of the last day assigned for the census enumeration. This means that:
All persons must be enumerated within the census reference period. Note, between the census night and the time of enumeration, the composition of a particular household might have changed.
Children born up to the time the enumerator comes to the household are to be enumerated, but children born after the enumerator has completed the household, even if the birth occurred within the census enumeration period, should not be enumerated.
Similarly, persons who died within census enumeration period, but before the enumerator come to the household are not to be included, and any death that occurred after the enumerator has completed the household is not to be erased even if it occurred within the census enumeration period but after the visit of the enumerator”
Note: No enumeration should take place before or after census period unless authorised by the Chairman (NPC). Only persons physically present at the time of enumeration shall be eligible to be enumerated.