The U.S. Environmental Protection Agency has rolled back Obama-era clean car standards that would require vehicles made between 2022 and 2025 to get 51.4 miles per gallon of gasoline (about 36 mpg under typical driving scenarios). While the oil industry and some automakers celebrated the decision, other car manufacturers, like Ford and Honda, say they face losses in their investments in making their vehicles run cleaner. But the biggest loser will be the climate (and those forced to breathe polluted air). The transportation sector is the nation’s biggest contributor of greenhouse gas emissions, in large part due to gas-guzzling passenger vehicles. If implemented, the clean car standards would have saved an estimated 1.2 billion barrels of oil, along with 540 million metric tons of carbon dioxide emissions, over the course of their lifetime. The weakening of these safeguards may also cause a ripple effect among carmakers across the globe. The good news? California, which has major influence in the domestic auto market, plans to stick with its clean air standards and is gearing up for a legal fight.