There have been a fair number of executions of local government officials.
It's much easier to make the case "corruption at the local level is really bad" vs. "the central government isn't corrupt" -- I'm just saying the local people are worse than the central government in a lot of ways.
The least corrupt entity is the PLA, which has the most power at the national level.
The most corrupt things are land sales, which are handled at the local level.