President Trump's ill-advised rollback of tailpipe emissions standards will choke progress toward cleaning the air and cutting the costs to drive a car or truck.

The Environmental Protection Agency under Trump, headed by the heavily conflicted Scott Pruitt, announced plans Monday to reduce air quality standards without saying by how much. That will come later. The standards were most recently upgraded by President Barack Obama to curtail air pollution's harmful effects on human health and climate change, including rising sea levels, more frequent flooding, longer droughts, and an increase in wildfires.

Obama's goal was to double the average fuel economy of new cars and trucks to 54.5 miles per gallon by 2025. Not only would the standards reduce our dependency on oil and cut pollution, they would save consumers money.

A former EPA official estimates that fuel savings to consumers under the Obama standards could be $1.7 trillion over the lives of their vehicles. In an opinion piece in the New York Times, Margo Ogre, former director of the EPA's Office of Transportation and Air Quality, further argues that rolling back the standards would actually hurt the auto industry's "long-term competitiveness and stability."

She's right. Who wants to buy an American car that costs more to operate than an equally good foreign car? But automakers complained that it costs them too much to clean up emissions, and Pruitt listened.

This is the latest attack on environmental standards. It  comes after the EPA has downgraded emissions standards at coal plants, opened the coasts to offshore oil drilling, and weakened protections against toxic runoffs into estuaries. On top of that, Trump has made it harder for the agency to enforce surviving standards because he has targeted the EPA for funding cuts.

States have tried to stand up for their residents against the administration's rollbacks.After the administration indicated in June that it would relax auto emissions standards, a dozen states, including Pennsylvania, said they'd fight it. But the EPA is ready for them. In this latest edict, the EPA singled out California with a plan  to strip its ability to set higher auto emission standards, which are protected by a section of the Clean Air Act. The state is getting ready for a court battle. It should.

Scientists have long studied the health effects of air pollution, much of it literally driven by tailpipe emissions. Dirty air has been cited as a factor in asthma, heart and lung disease, and premature death. Children and the elderly are especially vulnerable to air pollutants.

The EPA has the administrative power to roll back some of these standards. Public and political pressure are the best antidotes to this latest reckless act.

Congress should put pressure on the administration to care for our environment. That may sound like a long shot, but consider that Republicans, who now control Congress, are worried that the House could flip to Democrats in the 2018 elections. They are vulnerable to public opinion, which has favored environmental protections — even over economic growth — with few exceptions, according to an analysis of Gallup polls dating back to 1987.

That means voters favoring the environment can exert real pressure in the upcoming elections — and they should.