Eighteen states on Tuesday sued President Trump’s administration over its push to “reconsider” greenhouse-gas-emission rules for the nation’s auto fleet, launching a legal battle over one of Barack Obama’s most significant efforts to address climate change. Environmental Protection Agency Administrator Scott Pruitt in April said he would revisit the Obama-era rules, which aim to raise efficiency requirements to about 50 miles per gallon by 2025. Pruitt’s agency said that the standards are “based on outdated information” and that new data suggests “the current standards may be too stringent.” But in the lawsuit, the states contend that the EPA acted “arbitrarily...