Chinese regulators have unveiled new controls limiting access to overseas websites. The move, announced Sunday, comes as China’s population of online users increased to 731 million.

The Ministry of Industry and Information Technology said that for the next 14 months it will move against Chinese firms providing unauthorized Internet connections, including virtual private networks. “Unless approved, all basic telecommunication companies and Internet access service providers are barred from setting up or renting special lines (including VPNs) to carry out cross-border operations,” the ministry statement said.

The crackdown reflects a market showing “signs of disorderly development that requires urgent regulation and governance,” the MIIT said. Closing loopholes, such as VPN’s which are widely used to access websites that are blocked in China, is intended to “strengthen “cyberspace information security management.”

The timing and duration of the move coincides with the upcoming series of political events that include the once every five years national congress of the Chinese Communist Party in late 2017, and the once every five years renewal of the Politburo Standing Committee in early 2018. Those may see further consolidation of power around President Xi Jinping, and in that time criticism is unlikely to be tolerated.

A crackdown on the use of VPNs was previously operated in March last year during the National People’s Congress meeting.

According to data from the China Internet Network Information Center (CNNIC,) the country’s online population grew by 6.2% in 2016 rising from 688 million at the end of 2015. E-commerce was a key driver of growth in usage. So too was access via mobile devices. The number of people using mobile Internet connections was 695 million, meaning that for most newcomers and for many people in China the Internet is a mobile-only experience.

It is also a largely Chinese experience. China already operates one of the strictest Internet security regimes through an army of civil servants and battery of technology, frequently characterized as the great firewall of China. China currently blocks Google, Facebook, Twitter and YouTube, as well as publications including the New York Times. China is one of the few places in the world where Netflix is not allowed to operate and it recently banned augmented reality game PokemonGo. According to online monitoring organization GreatFire.org, China blocks access to 172 of the world’s top 1,000 Internet domains, and two thirds of the Wikipedia pages that it has tested.