Next up for a Trump demolition: perhaps the Obama administration’s draconian smog rule, which deemed even pristine national parks too polluted.

The Washington Post reports:

The Trump administration has given its strongest indication to date it may not stand in the way of lawsuits aimed at undoing Obama-era environmental protections for smog-forming pollutants.

In a court filing, the Environmental Protection Agency sought on Friday to postpone oral argument in a case involving an Obama-era standard limiting an air pollutant that forms smog, arguing it needs “adequate time to fully review” the rule.

The move raises questions over whether the Trump administration will defend the rule, which was criticized by several industry and Republican officials as too stringent and many environmental and public health advocates as too lax.

Smog levels have already substantially decreased year-over-year. Nonetheless, the Obama administration’s 2015 smog rules mandate brought the smog standards down to 70 parts per billion— a standard that even Yosemite’s Turtleback Dome and parts of the Sequoia National Park fail.

The American Action Forum estimated the regulation would take a $56.5 billion bite out of the economy, also costing 240,000 jobs.

But even the EPA’s more modest cost estimates—which, at $1.4 billion in annual costs, are 40 times less than the American Action Forum estimated—made the rule “one of the most expensive regulations in history,” the New York Times reported.