If you want a cheap flight from Norwich to Shanghai, you've got zero airlines to choose from.
Shanghai Pu Dong Airport is just one of the airports in Shanghai. If you're not set on a specific airport, try changing your search from Shanghai Pu Dong Airport to Shanghai to see a broader range of flights – they might be cheaper.
If you're planning on going to Shanghai during this time, you could take a look at other airport options. Or you could try to get a last-minute bargain.