I just found a great website called The Environmental News Network. Here's the first article I found:
SACRAMENTO, Calif. -- California can move forward with its efforts to set the nation's first standards to cut tailpipe emissions from cars, light trucks and sport utility vehicles, the Environmental Protection Agency said...
California has special authority under the federal Clean Air Act to set its own vehicle emissions standards because it began regulating air pollution before the federal government did in the 1970s. Ten other states have adopted California's standards, and Maryland is considering doing so, but they have to wait to implement them until the EPA grants California a waiver.
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