From Bulbapedia, the community-driven Pokémon encyclopedia.
Commerce City (Japanese: コモダシティ Komoda City) is an anime-exclusive location in Kanto. It appeared in Curbing the Crimson Tide and was the stomping grounds of the troublesome Red Lightning.
The giant city is prone to strong gusts of wind because its density has created a wind-tunnel effect, which aids Red Lightning in getting around. Cars and a rail system help move Commerce City's people around. A large park with a lake provides some recreational space away from the city's hustle and bustle.
While May was about to journey to its infamous Fifth Avenue strip mall, she was confronted by Red Lightning. After her Squirtle was defeated and its face scribbled on, she reunited with Ash and his friends at the local Pokémon Center, only to realize the true scale of the menace.
Ash, his friends, and Team Rocket soon followed the culprit to a rooftop mansion and encounter Luna, a local girl who created the Red Lightning alter-ego to cope with her loneliness while her parents worked. A battle ensued between Red Lightning and Ash's Pikachu, and its disguise was quickly unraveled, revealing that Luna had attached several devices to her Scizor to give it its speaking abilities. May and her Squirtle then had a rematch against Scizor and won. Afterwards, Luna declared that she won't continue to cause the city anymore trouble.