The Bush administration has appealed a court ruling that struck down the U.S. EPA’s controversial mercury cap-and-trade plan. The earlier ruling by a three-judge panel of the D.C. Circuit Court of Appeals found the EPA violated the Clean Air Act when it enacted the mercury rule in 2005. The cap-and-trade system allowed dirtier power plants to buy the right to pollute from cleaner ones; 17 states and a number of advocacy groups sued to stop the program, saying it concentrates highly toxic mercury into pollution hotspots. Instead of cap-and-trade, they said, every power plant should have to reduce its mercury emissions. The administration is now appealing the case to the full D.C. Circuit; an electricity-industry trade group also filed an appeal petition asking for review.