Zhuang Rongwen has been appointed as new head of the Cyberspace Administration of China, it was announced on Wednesday. He takes over from Xu Lin, a close aide of Chinese President Xi Jinping. Xu, who ran the regulator since 2016, is expected to be promoted to head of international propaganda, though that has not yet been confirmed.

As head of the CAC, Zhuang will oversee an important and controversial department. The CAC enforces a policy known as “Internet sovereignty,” which gives the Chinese government a high degree of control of the Internet within mainland Chinese borders.

The sovereignty strategy means that many Western media and social media are prevented from operating in China. Facebook, Google, Twitter, Instagram and YouTube are all unavailable inside China. Media blocked from ordinary access include The New York Times, The Economist and Bloomberg.

In a quick-fire series of confusing events, Facebook was last month granted a business license to set up an innovation hub in the city of Hangzhou.  That appeared to be the product of years of business-diplomatic initiatives in China by Facebook founder Mark Zuckerberg. However, the permit appeared to have been withdrawn just days later, apparently after the CAC stepped in.

The CAC has recently been publicly criticized for not fully effecting the policies stipulated by Xi. That criticism, however, may be related to the period up until mid-2016 when it was headed by Lu Wei. Lu was this week formally charged with corruption, allegedly having accepted “huge amounts” in bribes, according to state media.