A federal appeals court late last week gave the U.S. EPA permission to begin enforcing a regulation that will force 19 states in the Midwest and South to cut sharply power-plant emissions that contribute to smog in the East. The feds say the new rule could remove 1.1 million tons of nitrogen oxide from the air each year, an amount equivalent to the pollution from 166 million cars. More than half the reductions would come from six states: Illinois, Indiana, Michigan, Ohio, Pennsylvania, and West Virginia. Industry groups and the states that lost the court ruling said they would consider an appeal to the Supreme Court; otherwise, the states have until October to submit plans to the EPA outlining how they will comply with the regulation and until May 2003 to be in compliance.