A waiver from the federal government has long allowed California to set its own stricter tailpipe emissions. But now, fuel companies are suing. On Wednesday, the Supreme Court will weigh whether ...

Under the Clean Air Act, states are generally prohibited from setting their own tailpipe emissions for ... in December was the Omnibus Low-NOx Emissions Rule, which imposes aggressive emissions ...

The move comes a day after the chamber voted to halt California standards to cut tailpipe emissions from medium- and heavy-duty vehicles, as well as curb smog-forming nitrogen oxide pollution from ...