Portland

Organic Gardening rates the Emerald City one of the nation's greenest, in part because residents drive two hours north every fall to the Common Ground Fair.

"Green is growing all over this coastal city--it has acres of parkland and trails... All city-owned diesel vehicles run on a mix of 20 percent vegetable-based biodiesel fuel and 80 percent regular diesel, and must adhere to an anti-idling ordinance."