The project is part of a pact between one of India's most powerful conglomerates and POSCO, giving the South Korean steel major a fresh opportunity to cash in on growing steel demand in the South Asian nation.
The pact to explore business opportunities, under which both will invest about $5 billion, covers industries such as renewable energy, hydrogen, and logistics, the companies said in Thursday's statement, without giving details.
"POSCO and the Adani group have agreed to explore business co-operation opportunities," they said, adding that one of these was putting up a green, environment-friendly integrated steel mill at Mundra in the coastal state.
Adani did not immediately respond to a query on individual investments.
POSCO now runs a 1.8-million-tonne cold-rolled and galvanized mill in the western state of Maharashtra, supplying automotive steel to India's leading automakers.
It dropped plans a few years ago for what was seen as India's biggest foreign investment, a $12-billion steel plant project with annual capacity of 12 million tonnes in the eastern state of Odisha, stung by inordinate delays in land acquisition.
Adani aims to invest $20 billion in renewable energy in the next decade, saying it will also strive to make its port business a net-zero carbon emitter by 2025. Its flagship, Adani Enterprises, is India's biggest coal trader, having faced opposition from climate activists for its push to operate Australia's Carmichael mine, one of the biggest greenfield coal projects of recent years.
(Reporting by Nallur Sethuraman in Bengaluru and Mayank Bhardwaj in New Delhi; Editing by Clarence Fernandez)