BEIJING: The Chinese government is attempting to tighten its grip on web content viewed by its citizens via a six-month campaign against pornography, rumours and slander.

The Ministry of Public Security says: "The boom of pornographic content on the internet has contaminated cyberspace and perverted China's young minds." In addition, says ministry official Zhang Xinfeng, "content that spreads rumours and is of a slanderous nature" would also be blocked.

According to OpenNet Initiative, a partnership of British and US universities that studies online censorship in China, authorities use a mix of techniques to filter undesirable content and prevent people within is borders from talking about forbidden topics.

Filters at the gateway to the country's data network block some websites and further filtration is carried out by individual internet service providers.

Data sourced from The Times Online (UK); additional content by WARC staff