Italy's government has been trying to find a bidder for the plant, Europe's largest by output capacity
JSW Steel Ltd has joined one of two investor groups vying to take over Italy's loss-making Ilva steel plant, a source with knowledge of the matter said on Monday.
The steel firm owned by billionaire Sajjan Jindal has signed an agreement with Italian state lender CDP, businessman Leonardo del Vecchio's holding company and steelmaker Arvedi to make the bid, the source said.
A second source said the firm had confirmed its interest in joining the bid, but did not know if a formal agreement had been signed.
JSW Steel, one of India's top domestic steel producers, did not immediately respond to a request for comment.
Italy's government has been trying to find a bidder for the plant, Europe's largest by output capacity, since taking it over last year in a bid to save jobs and clean up its polluting factories.
Judges put key parts of it under special administration in 2012 following accusations it had caused serious health problems in the surrounding Puglia region in southern Italy.
The world's largest steel producer Arcelor Mittal has also offered to buy Ilva, in a joint bid with Italy's Marcegaglia.
Neither bidder has said how much they would offer for the plant, but a source familiar with the matter told Reuters in June the CDP-led group would probably bid between 500 million and 1 billion euros ($1.06 billion).
The sale is now expected to be completed in early 2017. Officials from the Italian environment ministry had been due to deliver their verdicts on the bidders' proposals by November 13.