The EPA has loosened or eliminated a lot of regulations since President Trump took office, but last week the agency announced it would tighten regulations on emissions of nitrogen oxides from heavy trucks such as semis.

The EPA notes that smog-forming NOx emissions from heavy trucks fell 40 percent between 2007 and 2017 after the agency last tightened standards in 2001. (It predictably takes several years after new regulations are passed for air quality to improve as new trucks trickle out onto the roads and old trucks are retired.)

DON'T MISS: Trump administration releases proposal to weaken fuel economy, emissions standards

It estimates that as cars get cleaner and more efficient, heavy trucks will account for a third of transportation-related NOx emissions by 2025.

EPA Acting Administrator Andrew Wheeler

EPA Acting Administrator Andrew Wheeler

The Cleaner Trucks Initiative that the EPA announced so far has no teeth or even skin. The agency said specifics of the proposal—how much emissions will be cut, under what conditions, and by when—won’t be released until 2020 when it plans to issue a new notice of proposed rulemaking.

READ THIS: EPA plans to roll back emissions standards on power plants

It’s worth remembering that 2020 will be the next presidential election year, when the administration may have political points to score.

“Today’s announcement makes clear that reducing NOx emissions from heavy-duty vehicles is a clean air priority for this administration,” said Assistant Administrator Bill Wehrum with the EPA’s Office of Air and Radiation. “EPA’s Cleaner Trucks Initiative is an important signal to all interested stakeholders that we will work hard on reducing emissions while producing a more effective and efficient program.”

CHECK OUT: EPA dissolves boards of pollution scientists

Acting Administrator Andrew Wheeler said, “The Cleaner Trucks Initiative will help modernize heavy-duty truck engines, improving their efficiency and providing cleaner air for all Americans.”

Along with the stricter NOx emissions standards, Wheeler said in a statement that the proposed rule will streamline compliance and certification procedures for truck emissions. “Through rulemaking and a comprehensive review of existing requirements, we will capitalize on these gains and incentivize new technologies to ensure our heavy-duty trucks are clean and remain a competitive method of transportation,” he said.