what the island was like before the population grew
Miceland is an island from the first season episode "Population Bomb." The island was inhabited by mutated mice that were changed into humanoid creatures as the result of fallout from a nuclear bomb that was tested. It was unknown when the bomb was tested.
The island was once also a beautiful paradise with sunshine, clear air, water, and enough food because their families were small. As a result, the Micelanders led a peaceful and simple life. But in time, the number of children grew and grew. They had built cities to the point where there were no trees left. As a result of the smoke from their factories and the exhaust from their cars, the island quickly grew into a single large city, with a brown, foul, and odorous sky. Due to the poor quality of the air, a second city was erected underground.
Another city underground
All of the indigenous animals and birds that had coexisted with the Micelanders were wiped out. Some they ate, and some they drove to the sea. Now they have memories of these birds and beasts in their museums. So without vegetation and game, the Micelanders try their hand at fishing in their oceans. But they used it to dump their sewage and garbage. Now there are fewer fish and more mouths to feed. The population kept growing and couldn't be stopped because the desire for a big family is rooted in their culture. Worse of all, the island is under the dictatorship of the tyrannical, iron-fisted General Claw.