How is china censoring the internet?

[Louisee]

iv recently started studying internet regulations for my A2 media but i want to know more about how china is censoring the internet. I know they have different sites for facebook and twitter etc but what are these sites called? and what sorts of things are blocked and why? iv tried looking online but there is so much information about all the different topics within censoring the internet, its hard to find the right thing especially when trying to get through all the news reports there is on the topic, hope someone can help me understand