Mobile Fighter G Gundam

Mobile Fighter G Gundam summary:

In the Future Century (F.C.), humans have ruined the Earth. Much of mankind has abandoned Earth for space colonies, with each country on Earth having a corresponding space colony. Instead of having wars, a "Gundam Fight" is held every four years, where a representative will pilot a Mobile Fighter and compete with other Gundams until only one is left. The winning country is allowed to rule the Earth for four years until the next Gundam Fight.