India - Housing Condition and Migration Survey: NSS 49th Round, Schedule 1.2, January - June 1993 

RURAL:The first-stage sampling unit ( FSU ) , is also the unit of survey in rural areas is the census village. In most of the cases, it is the 1981 census village. It is indicated in the sample list whether the sample FSU is the 1981 census village or some other ( i. e. 1991 or 1971 ) census village
URBAN:The NSS Urban Frame Survey ( UFS ) block is the unit of survey as well as the first-stage unit for urban areas. Different UFS frames according to the completion of the urban frame survey and the availability of the relevant records have been used for selection of FSUs. For newly declared towns of 1991 census for which UFS frame has not been available for selection the 1991 census Ebs are the units of survey as well as FSUs.