Salem, with a population of 8,30,000 is the sixth largest city of Tamil Nadu by population. The literacy rate is 84.4% and Tamil is the most widely spoken language. Located at an elevation of 912 feet, Salem is surrounded by hilly terrain and the River Thirumanimutharu flows through the city, dividing it into two. The total population of Salem District is 3.5 million, the literacy rate is 72.9% and 49% are in the working age. This includes 42 percent of the working age population that is engaged in agriculture, 8 percent in the household industry, and 50 percent in services and industry. Salem is known for its textile industry, with a number of spinning, weaving and dying units, for its Sago factories and the Salem Steel Plant of the Steel Authority of India. Salem was an important part of the Chera dynasty, Poligars and Vijaynagar Kingdom. The region was captured by Hyder Ali during the early 18th century after the Mysore-Madurai war and was ceded to the British in 1768.