Colorado is tightening its air quality regulations and requiring at least 5 percent of the vehicles sold in the state by 2023 to emit zero pollution.
The rule approved Friday by the state Air Quality Control Commission applies to auto manufacturers, not buyers.
It's aimed at boosting electric vehicle use in a state struggling to control air pollution in heavily populated areas.
Green Car Reports tracks developments in low-pollution vehicles and says Colorado is the 11th state to adopt zero-emissions requirements.
The auto industry groups Global Automakers and the Alliance of Automobile Manufacturers praised the rule. They say they have worked with Colorado officials on structuring the requirement.
Environmental groups also welcomed the standards. The Colorado Freedom to Drive Coalition called them costly and futile.
