Online pornography, violence, terror and superstition will be cleaned up, the internet regulator Cyberspace Administration of China (CAC) said in a statement.
The Internet had become a main source of information and socialising for minors. However, they are exposed to vulgar content, state-run Xinhua news agency reported, quoting CAC deputy head Ren Xianliang.
He said that it posed a threat to the future of the Internet and the nation as a whole.
Along with the campaign, the CAC also plans to crack down on illegal religions, harmful information from overseas and information published by unlicensed journalists and media.
