Google have stopped carrying advertisements in China for two sites that help web users in the country find ways to get around censorship laws. Read more at warc.com
There are sites that offer virtual private network services. These services are widely used in the country for getting around government surveillance and it's 'Great Firewall' policy of blocking sites and content if it deems unsuitable.
It was in the last week that Google had refused to sell its ads to Chinese users. Nine years ago Google had shut down its search engine in China after it was hit by cyber attacks and blocking by the Government.