The Environmental Protection Agency under Biden in 2024 set stringent vehicle emissions rules that aim to cut fleetwide tailpipe emissions for cars and light trucks by nearly 50% over 2026 levels in 2032 and drastically increase new electric vehicles.

The EPA forecast last year that between 35% and 56% of new vehicles sold between 2030 and 2032 would be electric to meet tough vehicle pollution rules. Senate Republicans also want to reverse the EPA rule’s new emissions limits for medium- and heavy-duty vehicles like delivery trucks, garbage trucks, public utility trucks, school buses and tractor-trailers.

The Senate parliamentarian ruled rolling back the EPA rules would need 60 votes to pass in the 100-seat chamber, rather than the simple majority other elements of the tax and spending package would need under a complex budget process Republicans are invoking to bypass Democratic opposition.

The regulation was among the most significant environmental rules implemented under Biden, who made tackling climate change a key pillar of his presidency.