Supreme Court upholds cross-state pollution rule

In a 6-to-2 ruling, the United States Supreme Court has upheld the U.S. Environmental Protection Agency’s (EPA) authority to place limits on pollutant emissions that cross state lines and harm the air quality of downstream states. The ruling reinstates EPA’s Cross-State Air Pollution Rule (CSAPR), under which fossil fuel-fired power plants in 28 Midwestern and Appalachian states must control their emissions of nitrogen oxides (NOx) and sulfur dioxide (SO2), which contribute to high levels of soot and smog in the eastern states. The upwind states and the electric power industry had challenged the rule on the grounds that it trampled on states’ rights, and the U.S. Circuit Court of Appeals for the District of Columbia upheld that challenge in 2012. In overturning the appellate court’s ruling, the Supreme Court affirmed that the Clean Air Act (CAA) authorizes EPA to impose standards on states that don’t adequately control downwind air pollution. “In crafting a solution to the problem of interstate air pollution, regulators must account for the vagaries of the wind,” Justice Ruth Bader Ginsburg wrote for the majority.