The Environmental Protection Agency is on the verge of restoring California’s ability to set strict tailpipe emissions limits, according to news reports, while at the same time looking at adopting a version of the state’s stringent rules for heavy-duty trucks in an effort to cut smog-forming pollution.

The EPA’s restoration of California’s Clean Air Act waiver reverses the Trump administration’s revocation, and the new truck rule aims to drastically reduce nitrogen dioxide emissions from trucks.

Nitrogen dioxide pollution can cause and aggravate respiratory diseases, including asthma and certain kinds of cancer. It can also react with water and oxygen in the atmosphere to form acid rain. The last time the EPA updated emissions limits for heavy-duty trucks, in 2001, it cut nitrogen dioxide by 95 percent over 10 years. That caused nitrogen dioxide pollution to fall 40 percent nationwide.