GENEVA • An appeals board of the World Trade Organization reversed much of an earlier ruling against the United States on Monday, but it said U.S. duties on Indian steel broke WTO rules and asked the United States to bring them into line with its regulation.

In one of the most complicated appeals decisions ever handled by the 19-year-old trade watchdog, the WTO's Appellate Body reversed much of a ruling by a three-person panel in July, which said the U.S. duties had wrongly penalized India for subsidizing steel exports by Tata Steel.

The case involved U.S. duties imposed because a portion of the iron ore used to produce Indian steel pipe came from India's top iron ore miner NMDC, a state-run company that supplies steelmakers such as Tata and Essar.

An unnamed Indian official told Reuters when the case was launched in 2012 that the United States argued NMDC was selling the iron ore "for a song" and therefore implicitly subsidizing a private-sector enterprise.

U.S. companies Allied Tube and Conduit, JMC Steel Group, Wheatland Tube and United States Steel Corp., the owner of local steel mill Granite City Works, had petitioned the government in 2011 for import relief

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