(Bloomberg) -- General Motors Co. faced the prospect of needing to cut production of gasoline-fueled vehicles if electric-vehicle sales failed to grow as needed under ambitious fuel economy requirements enacted by President Joe Biden, company Chief Executive Officer Mary Barra said.

Fuel efficiency standards now being rolled back under President Donald Trump would have required a fleet average of about 50 miles per gallon by 2031. That effectively meant that most carmakers would have to get more than half of their sales from EVs by that time.

If those EV sales didn’t materialize — and the rules weren’t reduced by Biden in response — GM would have had to limit sales of gasoline-powered vehicles and possibly shut down some of its production, Barra said at the New York Times Dealbook conference in New York on Wednesday.

“We were going to have to start shutting down plants,” Barra said.