graffiti an art or a violation

Graffiti is a form of creativity that is poured on a medium, art is often encountered on the walls and other public equipment, because most of the media used is a public good is one branch of this art caused a controversy, on the one side of the perpetrators think that what is they are doing is a form of expression for their creativity, on the other hand, local authorities in this regard is the apparatus that they are doing is a violation because it is considered to have damage and littering the city, the two sides are both considered correct