Indian Standard Classification System (ISC) was adopted by Bureau of Indian Standards is in many respects like the Unified Soil Classification (USC) system. Soils are divided into three broad divisions: ● Coarse grained soils, when 50% or more of the total material by weight is retained on 75 micro IS sieve. ● For fine grained soils, when more than 50% of the total material passes through 75 micron IS sieve. ● If the soil is highly organic and contains a large percentage of organic matter and particles of decomposed vegetation, it is kept in a separate category marked as peat (Pt). In all there are 18 groups of soils: 8 groups of coarse grained, 9 groups of fine grained and one of peat.