Yūgai Toshi (有害都市, "Poison City") is a Japanese manga series written and illustrated by Tetsuya Tsutsui.

Created in response to what amounted to a ban of Tsutsui's previous work Manhole by the government of Nagasaki Prefecture,[1] Yūgai Toshi addresses censorship in Japan and follows fictional events similar to the circumstances of Manhole's ban.

In 2019, the Japanese government cracks down on censorship in the lead-up to the 2020 Summer Olympics, making any material they deem "obscene" increasingly difficult to publish.

During this time, manga author Hibino Mikio attempts to publish Dark Walker, which centers around a contagious disease that turns people into cannibals overnight.

Written and illustrated by Tetsuya Tsutsui, Yūgai Toshi started in Shueisha's seinen manga magazine Jump X [ja] on April 10, 2014.