Construction activity creates physical assets in a number of sectors of the economy. Construction sector has two key segments: (i) Buildings, falling into one of the following categories; residential, commercial, institutional and industrial ;and (ii) Infrastructural such as road, rail, dam, canals, airports, power systems, telecommunication systems, urban infrastructure including water supply, sewerage, and drainage and rural infrastructure. Assets once created also need to be maintained. Many upstream economic activities depend upon the construction sector. It is roughly estimated that 40-45 per cent of steel; 85 percent of paint; 65-70 per cent of glass and significant portions of the output from automotive, mining and excavation equipment industries are used in the construction industry.