From the Guardian: Shanghai’s Communist Party Chief sacked:
The rivalry between China's two most powerful cities is a factor. Shanghai is the powerbase of Hu's predecessor as president, Jiang Zemin. Under his protection the local party hierarchy was able to keep hold of all of the city's top political posts for 15 years, avoiding the rotation system that applied in every other province.
Partly as a result, critics accused the "Shanghai gang" of running one of the least transparent governments and most tightly controlled media environments in the country.
Of course you’d have known all about this if you’d been hanging out here a couple of weeks back.