Within each district of a State/ UT, two basic strata were formed:
(i) rural stratum comprising of all rural areas of the district and (ii) urban stratum comprising of all the urban areas of the district. However, if there were one or more towns with population 10 lakhs or more as per population census 2001 in a district, each of them also formed a separate basic stratum and the remaining urban areas of the district was considered as another basic stratum.