This area is an uninhabited place, but with some survivors. Most people in this world have fled due to Mr. Glutton, a Guzzlord. The area is a massive ruins of skyscrapers and other parts of a city, most of which matching Hau'oli City, with Guzzlord found at the end

Non-Alolan Evolution
If you evolve your Pikachu, Exeggcute or Cubone here, they will evolve into the Kantonian forms