A virtual private network (VPN) extends a private network across a public network, such as the Internet. It enables a computer to send and receive data across shared or public networks as if it is directly connected to the private network, while benefiting from the functionality, security and management policies of the private network. A VPN is created by establishing a virtual point-to-point connection through the use of dedicated connections, virtual tunneling protocols, or traffic encryptions.

If you are traveling abroad and using VPN in a state where there are some questions, in this case China, it is not illegal to use VPN for your personal needs but do not use it for political reasons. 

"Is it illegal to Use a VPN in China to access blocked websites?

No, not at all. Although it is illegal to operate a VPN business in China, there is no law against individuals using an overseas VPN. What you do after you connect to the VPN is another matter. If you are using a VPN to spread political messages or cause trouble for the government then you may be breaking other laws but connecting to a VPN in and of itself is not illegal. If you are using a VPN to watch YouTube or Netflix or use Facebook then you have nothing to worry about, you are not doing anything illegal. While using a VPN is legal it's also legal for the government to block VPN traffic when and as they feel necessary and they do this often.

In January, 2017 the government has announced a crackdown against Chinese Telecom companies offering unlicensed VPN services. It has nothing to do with using a personal VPN service that operates outside of China, which is still not illegal."

For information on the Pomona College VPN, please review the knowledge base articles referenced in the inset.