The U.S. Supreme Court ruled that the U.S. Environmental Protection Agency (EPA) can reinstate limits on power-plant pollution that blows across state lines.

The 6-2 decision is a win for the EPA which has been trying to implement the Cross-State Air Pollution Rule since it was introduced in 2011. The rules were challenged by a coalition of upwind states and industry, which prevailed in lower courts.

Justice Ruth Bader Ginsburg writing for the majority that the EPA must have leeway to confront the “complex challenge” of interstate pollution.

“Most upwind states propel pollutants to more than one downwind state, many downwind states receive pollution from multiple upwind states, and some states qualify as both upwind and downwind,” she wrote. “The overlapping and interwoven linkages between upwind and downwind states with which EPA had to contend number in the thousands.”

Ginsburg was joined by Chief Justice John G. Roberts Jr. and Justices Anthony M. Kennedy, Stephen G. Breyer, Sonia Sotomayor and Elena Kagan. Justices Antonin Scalia and Clarence Thomas issued a scathing dissent, which Scalia read in part from the bench, and Justice Samuel A. Alito Jr. recused himself from the case.

The regulation stands to affect about 1,000 power plants in the eastern half of the U.S. that may have to adopt new pollution controls or reduce operations, The Wall Street Journal reported. The decision could further threaten the viability of some aging coal plants, which already face other market and regulatory pressures.

The EPA’s approach had been challenged by affected states, including Ohio, Michigan and Texas, as well as owners of coal-fired power plants like Southern Co. and Xcel Energy Inc. Those firms argued the EPA overstepped its legal authority and the rules were unfair to plants in upwind states.

"EPA's cost-effective allocation of emission reductions among upwind states, we hold, is a permissible, workable and equitable interpretation" of the Clean Air Act, Justice Bader Ginsburg wrote for the majority.

The ruling comes on the heels of another court victory for EPA air-pollution rules. The U.S. Court of Appeals for the District of Columbia Circuit on April 15 upheld the nation's first-ever national standards requiring power plants to cut emissions of mercury and other hazardous pollution.

The cross-state regulation was the EPA's latest attempt to implement a Clean Air Act provision in which Congress required states to be good neighbors when it comes to air pollution. The EPA rule focused on reducing emissions of nitrogen oxides and sulfur dioxide, both associated with higher rates of heart attacks and respiratory illnesses. The agency said its rule would improve air quality in thousands of counties in the eastern, central and southern U.S.

Justice Scalia signaled strong disagreement with the ruling by reading parts of his dissent from the bench, saying EPA hadn't followed the approach set forth by Congress. "Today's decision feeds the uncontrolled growth of the administrative state at the expense of government by the people," he said.

It is unclear what effect the rule might have on the coal industry, already battered by rules such as tighter limits on mercury emissions and an Obama administration proposal to limit greenhouse-gas emissions from new power plants, as well as market pressure from cheap natural gas and relatively weak power demand. The National Mining Association, a party to the case, said it is "gravely concerned with the latitude afforded EPA to pre-empt states before they have had a reasonable chance to act."