The 2008 Summer Olympics are history, and the Chinese government's attempts to reduce its capital city's infamous smog appear to have been a modest success. With restrictive measures in place like closing factories and limiting drivers to using their cars only every other day, particulate matter in the Beijing skies dropped 20 to 40 percent compared to last summer—but not everyone agrees that the government's actions were the cause.
Though China's clean-up efforts were "extreme but temporary," they reflect the growing concern about greening the games, according to Jonathan Lash, the president of the World Resources Institute. "If you talked about green issues at the Olympics 20 years ago, nobody was paying attention," Lashsaid.