More than 60 video-streaming and download websites on the mainland have been warned or ordered to shut down by the State Administration of Radio Film and Television (Sarft). Most of the blacklisted sites seriously or repeatedly violated regulations about internet streaming media by offering sexually explicit, pornographic, terrifying or violent content, Sarft said in an announcement posted on its website. Thirty websites were ordered to stop posting audio-visual content while another 32, including the popular video-sharing site tudou.com, received warnings. The official efforts were aimed at maintaining a healthy, positive and orderly internet environment for the public, the statement said. Similar reasons have been offered for Beijing blacklisting Tang Wei , the lead actress in the film Lust, Caution. An unnamed senior Sarft official told The Beijing News on Tuesday that Tang's commercials had been pulled to reduce her popularity with young people. Tang has been criticised by mainland conservatives for posing nude in the film. Although Sarft seemed to be worried most about adult content, its latest censures highlight other no-go areas, such as television programmes and film documentaries that threaten national security or the national interest. An administration official denied the crackdown was related to riots in Tibet because the operation was completed last month, before the protests in Lhasa and elsewhere. According to the official statement, the two-month campaign started in December. 'It is a coincidence of timing,' the official said. Tudou.com, one of the largest video-sharing platforms and funded by overseas venture capital, had crossed some official boundaries a number of times, Sarft warned. The website tightened its scrutiny on video uploads and sharing after Sarft discovered that some of the site's members had posted pornographic content. 'Approval [for uploading video] used to be prompt and sometimes instantaneous ... but recently it seems to take forever,' Hong Liang , a user in Beijing, said yesterday. A Tudou customer service representative confirmed the delays. Any upload, she said, would take at least a day to get approved. On Sarft's website, a few netizens have complained about the latest clean-up campaign. 'Who gives you the power to do this, to ban everything you don't like without considering what that we, young people, need and desire?' one contributor posted. 'Don't try to act like a saviour of adolescence ... It won't work. The internet has been here for years ... you cannot catch up.'