Gas mileage standards passed by the Obama administration are in the process of eliminating hundreds of millions of vehicles’ worth of pollution by 2025.

That’s far less smog-inducing pollution exacerbating the asthma and other lung ailments that are far too common in Maine, and less pollution contributing to the climate change that is raising sea levels along the Maine coast, rapidly changing the Gulf of Maine and altering the composition of our forests.

The mileage standards also are expected to save drivers more than a billion dollars in fuel costs, while pumping up domestic manufacturing as well.

All along, the auto industry proved it could make cars that are better for the environment if it had the incentive.

This week, however, the Trump administration is set to take that incentive away. The Environmental Protection Agency is expected to announce it is rolling back the Obama-era standards, which when enacted in 2012 called for the average miles per gallon of new vehicles to double by 2025.

The administration’s move is certain to draw a response from the state of California, which for years has gotten a federal waiver allowing it to set its own, stricter mileage and emissions standards, and has done so with an eye toward cutting pollution and the use of fossil fuels. Twelve other states, including Maine, now follow California’s lead.

But automakers have decried having two standards – one for California and like-minded states, and one for the rest of the nation. Some even want the EPA to revoke California’s waiver.

Whatever the case, loosening the standards in any way would slow the impressive gains made over the past few years and have profound effects on air quality in Maine.

Automakers have made a lot of headway on gas mileage in the last decade-plus. The average fuel economy for car-based SUVs went from 20 mpg in 2005 to 25.3 mpg in 2015. Truck-based SUVs went from 16 mpg to 22 mpg.

Overall, gas mileage hit a record high average of 24.7 mpg in 2016, with another record expected once 2017 numbers are finalized.

The actions taken by the Obama administration beginning in 2012 and extending through 2025 are expected to cut emissions so broadly that it would be the equivalent of taking 422 million cars off the road. Drivers are expected to save $1.7 billion in fuel costs, and oil consumption would be cut by 12 billion barrels.

The pursuit and fulfillment of the Obama-era standards would not only cut the amount of greenhouse gases released into the atmosphere, with the goal of curtailing the climate change that affects Maine in so many ways, it would also make Maine’s air cleaner.

A receiver of pollution from coal-fired power plants in the Midwest and heavily trafficked cities of the Eastern Seaboard, Maine suffers when other states do not take action against emissions. Under Administrator Scott Pruitt, the EPA has taken aim at the measures that protect Mainers, including arguing against the Clean Power Plan, which controls power plant emissions, and refusing to enforce strict ozone standards.

Now comes the shot against standards for auto emissions – the largest contributor to Maine air pollution. Automakers say the Obama-era rules are stifling, but they have had little trouble advancing the technology to meet them, and car sales have not suffered.

Cutting the standards, though, would certainly please automakers. It would also be on-brand for Pruitt, who doesn’t buy the clear science on climate change, and as EPA head has consistently backed industry over the environment.

But it would do nothing but hurt Mainers.