According to Jon Stewart:
From an interview with Charlize Theron, star of the movie "Battle in Seattle," about the Seattle WTO protests. It's a couple minutes in before they start talking about the WTO.
Which brings me to a related point. This is from an interview with Stuart Townsend, who directed the movie:
American democracy is challenged because the WTO can impose laws or sanctions on the U.S. without its citizens or government having any say in the matter. For example, the Clean Air Act was overturned because it was deemed an illegal barrier to trade. Which means Americans breathe dirtier air. (emphasis added)
Sigh. I think it's safe to say that anyone familiar with the case would agree that it is not completely accurate to state that the WTO Gasoline ruling "overturned" the Clean Air Act. Rather, it struck down one aspect of the Act because it discriminated against foreign goods. I know it's a lot to expect of a movie director to get the details of WTO decisions right. But at the same time, I have no doubt that he's getting his info from NGOs who follow these issues, because I've seen similar statements from them. The problem I have with these kinds of exaggerated and inaccurate criticisms of trade rules is that they undermine the many legitimate criticisms that can be made.
ADDED: In the comments, people have pointed out that some of my own language was not quite right. What I should have said was that the WTO ruling found one aspect of the related Regulation (not the Act) to be in violation of WTO rules.