WASHINGTON (AP) – In a blow to the fight against climate change, the Supreme Court has limited how the nation’s main anti-air pollution law can be used to reduce carbon dioxide emissions from power plants. By a 6-3 vote Thursday, with conservatives in the majority, the court said that the Clean Air Act does not give the Environmental Protection Agency broad authority to regulate greenhouse gas emissions from power plants that contribute to global warming. Instead, the EPA is limited to plant-by-plant regulation, the high court said. The court’s ruling could complicate the administration’s plans to combat climate change.