Each artist has an individaul style, but all artist share a commom aim: to draw attention to pollution in our cities. The UK's paul Curtis, better know as Moose, operates around Leeds and has been commissioned by a number of companies to make reverse graffiti ads.
Brazilian artist Alexandre Orion turned one of Sao Paulo'traffic tunnels into an amazing mural by scraping away the dirt. Made up of a series of white skulls, the mural reminds drivers of the effect their pollution is having on the planet. "Every driver sits in the comfort of a car, but they don't give any consideration to the price their comfort has for the environment and consequently for themselves," say Orion.