BEIJING: China’s cyberspace regulator on Thursday said that rules requiring data exports to undergo security reviews would be effective from Sept. 1, the first time it has given a start date for a new regulatory framework that will affect hundreds, if not thousands, of Chinese companies.The details of a new compulsory security review to be carried out by the Cyberspace Administration of China (CAC), which will be used to determine whether large quantities of Chinese user data in the possession of a private entity can be sent overseas, were also finalised and published on Thursday, the regulator said in a statement on its official WeChat account.