A. TISCO- The Tata Iron and Steel Plant, also known as Tata Steel, was the first steel plant to be established in India. It was founded by Jamshedji Tata in 1907 in Jamshedpur, Jharkhand. This plant was the pioneer of the Indian steel industry and is one of the oldest and most renowned steel plants in the country.

B. Durgapur- The Durgapur Steel Plant, located in Durgapur, West Bengal, was set up with technological assistance from the United Kingdom in 1962. It was one of the key initiatives taken to boost industrialization in the post-independence era of India, making it newer than Tata Steel but older than Salem Steel Plant.

C. Bokaro- The Bokaro Steel Plant, located in Bokaro, Jharkhand, was established as a collaboration between the Soviet Union and India in 1964 This plant was founded to produce high-quality steel and is a significant player in the Indian steel industry. 

D. Salem- The Salem Steel Plant is located in Salem, Tamil Nadu. It was established as a joint venture between the Government of India and a few foreign companies, including the United Kingdom's Nuffield Exports Limited and the Soviet Union. This plant started production in 1982.