The next level - the Township - is the second-most-ancient social unit, after Village. The purpose of the Township is to allow adjacent Villages to cooperate, trade, and mingle for greater cultural opportunities. It's also the unit of light industry. It consists of a collection of adjacent villages, plus a Town Center (located in a central location). Every Township has the goal of being self-sufficient in light industry.
The City is the next level. Its purpose is the same as the Township, but on a larger scale. It's the unit of heavy industry, and hence, every City has a goal of being self-sufficient in heavy industry (and hence, totally self-sufficient in all economic matters). It consists of many adjacent Townships, plus a centrally-located City Center.
The Eco-Region is a large geographic area of similar and interrelated climate, habitat, ecosystems, and resources. Its job is to make sure that natural resources in that region are shared equitably among all cities and communities, while preserving the ecosystem sustainably. For example, in a desert region whose people rely on a large lake for crop irrigation, the Eco-Regional government may manage the irrigation system to make sure every community gets water - and no community monopolizes and restricts it from the others.
The Eco-Regions are defined by the Council of the Planet.
The Planet is a single, interrelated body, and is thus governed as one. The Council Branch of the Planet is referred to as the High Council, since it holds the highest arbitration authority among humanity.
Here is a more elaborate chart, showing details about the Levels and Branches: