W04. Manufactured Urbanism. A sponge city is one that can hold, clean, and drain water in a natural way using an ecological approach. Fatal Floods attacks multiple cities in China in the annual monsoon season. “We have poured more than enough concrete.” says Kongjian Yu, the dean of Peking University. Sponge cities create the ability to reduce the effect on our urban footprint, as cities grow larger and larger.