The ruined world in Pokémon Pokopia represents the Kanto region. The game presents Kanto in a post-apocalyptic state, after humans have abandoned the planet and Pokémon habitats have deteriorated.
This setting gives Pokopia a recognizable connection to the earliest Pokémon games while allowing it to tell a different kind of story. Instead of traveling between Gyms, collecting badges, and becoming Champion, the player restores the landscape and helps Pokémon return to livable environments.
The Kanto connection is easy to miss because Pokopia does not simply recreate the region as it appears in Pokémon Red, Blue, or Yellow. Its version is damaged and largely empty, and the game’s central mystery concerns the disappearance of humans and Pokémon. Ditto eventually finds records and technology that reveal more about what happened.