California air regulators have unanimously approved the world's most stringent rules to reduce automobile tailpipe emissions that are believed to contribute to global warming, according to The Associated Press on September 27. The regulations are expected to cut exhaust from cars and light trucks by 25 percent and in larger trucks and sport utility vehicles by 18 percent. The move by the California Air Resources Board (CARB) came despite vigorous opposition from auto industry officials, who have threatened to challenge the regulations in court. Automakers have long argued that the board did not have the authority to adopt such sweeping regulations, accusing regulators of trying to indirectly regulate fuel efficiency - which is reserved to the federal government - and complaining that the regulations could not be met by current technology.