Polluted Guerrilla Promo

(Via: Invisible Red)

Imagine how much pollution each of us emits by driving. A guerrilla marketing campaign from World Wildlife Fund (WWF) showed how much carbon monoxide and pollution a car emits by leaving the car running all day with a huge balloon attached to the back. By the end of the day a huge black cloud revealed the statement "Drive one day less and look how much carbon monoxide you'll keep out of the air we breathe."

This is a bold effort to raise awareness on pollution. I don't know if its the most eco-friendly guerrilla marketing promotion because ironically they created so much pollution by leaving the car on all day for the length of the campaign to make a point about pollution.