Etching skulls on the side of the tunnel with nothing but water and a cloth.
Hailing from Brazil, Alexandre sees his art work as a way of getting an environmental message across to those who ordinarily wouldn’t listen. A few years ago he adorned a transport tunnel in Sao Paolo with a mural consisting of a series of skulls to remind drivers of the detrimental impact their emissions have on the planet.
The Brazilian authorities were incensed but couldn’t actually charge him with anything so they instead cleaned the tunnel. At first the cleaned only the parts Alexandre had cleared but after the artist switched to the opposite wall they had to clean that too. In the end, the authorities decided to wash every tunnel in the city, missing the irony completely, it seems.
--from environmental graffiti