Hokuto no Ken: Jubaku no Machi

In the 21st century, a nuclear war turned most of the Earth's surface into a desert wasteland, which also resulted in the contamination of the Earth's water supply. A man named Sanga has built the fortified haven of the "Last Land," where he rules as its dictator by monopolizing the city's uncontaminated water supply. When he learns that the neighboring residents of Freedom Village are trying to dig up a well for their own, Sanga sends his underlings to sabotage their effort. Kenshiro, master of Hokuto Shinken, gets involved in the conflict between the two regions after saving Tobi, an informant hired by Freedom Village.

(Source: Wikipedia)