The White House released the final version of its rules to roll back Obama-era auto emissions standards, taking a critical step toward completing what would be President Donald Trumps most substantial environmental change since taking office as the novel coronavirus pandemic rages.

The rule, called the Safer Affordable Fuel-Efficient (SAFE) Vehicles Rule and written by the Environmental Protection Agency and the Department of Transportation, would lower fuel economy standards for vehicles sold in the United States from 54 miles per gallon by 2025 to 40 miles per gallon.

By reducing regulatory burdens, thereby reducing regulatory costs, we will get more Americans into new, safer, cleaner vehicles, EPA Administrator Andrew Wheeler said in a call with reporters Tuesday.

The two-digit change carries 10-digit implications for climate change. Under the new standard, which could be implemented as soon as this spring, the U.S. auto fleet would emit nearly additional 1 billion metric tons of carbon dioxide over their lifespans on the road than they would under the existing rule. Thats nearly the annual emissions of Japan, the worlds fifth-largest source of planet-heating carbon dioxide.