Iron and steel industry is called the backbone of modern industry. It provides basis to many other industries, like ships, trains, trucks and autos are largely made of steel. The inputs for the iron and steel industry include raw materials such as iron ore, coal and limestone along with labour, capital, site and other infrastructure. The raw material is put in the blast furnace where it undergoes smelting. It is then refined. After refining the output obtained is steel. In India, iron and steel industry has developed taking advantages of raw materials, cheap labour, transport and market. Bhilai, Durgapur, Burnpur, Rourkela and Bokaro are some important steel producing centres in India.