In one of the most significant environmental cases to reach the U.S. Supreme Court in years, the high court yesterday heard arguments on whether the U.S. EPA overstepped its bounds in setting new clean air standards for ozone and particulates in 1997. Industry groups argue that the Clean Air Act, as interpreted by the EPA, provides so little guidance on how to set pollution limits that it amounts to an unconstitutional delegation of legislative power from Congress to the executive branch. And, if that argument doesn’t fly, industry also contends that the act ought to be interpreted to require the EPA to weigh the costs and benefits of each regulation it proposes. Unfortunately for business interests, the Supreme Court justices — even Chief Justice William Rehnquist and Justice Antonin Scalia — seemed skeptical of industry’s arguments and likely to side with the EPA interpretation of the law.