Gasmoxia is the home planet of Nitros Oxide, who soon returned home after his first defeat in Crash Team Racing. Not much is known about Gasmoxia at the time, only that it has a dark green moon. However, when Oxide returned as a boss in Crash Bash, in the boss level Oxide Ride, the battle against him was set in a city on Gasmoxia. Zam and Zem also come from Gasmoxia, but they are of a different species.
As said before, it is Nitros Oxide, Zam, and Zem's home planet. It looks like a dark green Moon surrounded by poisonous atmosphere. Possibly only gas-proof creatures with green skin can live there.