The Indian standard soil classification system (ISCS) was first developed in 1959. This classification system was developed by the Indian Standards Institution (now known as the Bureau of Indian Standards) with the aim of providing a standardized method for classifying soils in India.

The ISCS is based on the principle of particle size analysis, and it classifies soils into groups based on their physical properties. The classification system includes three broad categories - coarse-grained soils, fine-grained soils, and highly organic soils. These categories are further divided into sub-categories based on their particle size distribution, plasticity, and other properties.

The ISCS is widely used in India for various purposes such as geotechnical investigations, foundation design, and construction of roads, buildings, and other structures. It is also used by government agencies and private organizations for soil mapping and land-use planning.

In conclusion, the Indian standard soil classification system (ISCS) was first developed in 1959 by the Indian Standards Institution. It is based on particle size analysis and classifies soils into three broad categories with further sub-categories based on their physical properties. The ISCS is widely used in India for various geotechnical and engineering purposes.