The city beneath the surface.
Giha City is the city beneath Breezetop City - in other words, it's underground.
To get to Giha, one must navigate the abandoned catacombs of Breezetop City's original subway system, or the sewer system of the town. From there, a few access points by ladder take you down to Giha City, an underground city where absolutely no skylight can come through. Surprisingly, it's a well-populated place, thanks to the work opportunities the nearby Giha Mine provides. However, just as much as there are job opportunities, there is also rampant crime, with little to no people around willing to resist it.
Like the mushroom that slowly possesses a Paras into a Parasect, Giha City is the home of the criminals that secretly run the machinations of the brighter, cheerier Breezetop City directly above them. They are the highest entity that can even be considered an authority in this city.
Many of these criminal elements migrated here from Meiro City after the Ariados Fellowship drove them out. These relatively-newer gangs frequently clash with the established Giha gangs for turf. These brawls sometimes spill upward into Breezetop, but a few hands in local police coffers easily dissuade any more media coverage than they should.
Giha Mine is a mine outside the city. It has many passageways which can be traversed on foot or with the help of a mine cart. Many cavern-dwelling Pokémon live in the mine. Trainers are allowed access to the mine, but many dangers may await them there.
The only group of people who really care about the Giha City are the coalition of miners employed at the mine. The current foreman is an elderly man named Simon Marshall, who is also the Gym Leader. Simon and his loyal crew of miners attempt to protect the town much like the Ariados Brotherhood of Meiro. However, they are unable to drive away the criminals, so the best they can do is protect the secrets of the mine from criminals. For example, there is an underground river running through the mine with gold deposits. Mr. Marshall has his men find and relocate Nuggets from the stream and place them in a secret chamber to stop them from falling into the wrong hands.
Work at the mine is still very tough. The black dust in the mine causes lung problems for many of the miners, but the job has been made easier due to the natural digger Pokemon, Drilbur and Excadrill. Their renowned Drill Run technique saves a wealth of time and money excavating the mine. For many of the people struggling to get by in the underworld of Giha, the mole Pokemon provide a beacon of hope. However, there may not be a light at the end of the tunnel, as a new corporation is coming to town, and they wish to buy the mine and excavate it with heavy machinery (giving Simon a slice of the profit), which would lay off many of the workers trying to put food on their family's tables. But Simon stands firm... for now.
Giha City is based on Jiha Village from the anime Tengen Toppa Gurren Lagann. The gym leader, Simon Marshall, is named after Simon, the protagonist of the series, who hails from aforementioned village.
It's also inspired by The Under from Pokémon Colosseum.