Hello! Perhaps you meant squatting art o something like graffit,logos or patterns which squatters randomly spray onto the walls,I suppose. So we call them tu2 ya1 （涂鸦） or tu2 ya1 yi4 shu4 （涂鸦艺术）in chinese. But I don't really catch this sentence "as a center of underground art",sorry...

what do you mean by underground art?

though i don't know even one of these spots, i think there must be some, especially in those metropolises, such as beijing and shanghai. another problem is... how do u define the "centre" and the "art".

I dont konw