During a hike in the Great Smoky Mountains National Park in 1995, Don Barger climbed Chilhowee Mountain hoping to gaze across the valley below. All he saw was a wall of gray haze.

A 26-year-old federal regulation known as the regional haze rule has helped cut down on pollution over national parks, wilderness areas and tribal reservations, restoring some of the nation’s most spectacular natural vistas for outdoor lovers like Barger. But conservationists fear those gains may be lost after President Donald Trump’s administration announced in March the rule is among dozens of landmark environmental regulations that it plans to roll back.

Will the voters of Tennessee care? Maybe the roll back will make eggs cheaper.