Google Cloud egress traffic to china [closed]
Egress means all traffic leaving your network to the Internet. Any requests for web pages from your portal by users in China will cause egress to China because the responses are sent there from your network.
Google Cloud doesn't have any built-in service detailing your external connections. If the only thing you're running is a web site, then your site's access logs should presumably have IPs in them that you could use to determine which accesses came from different countries.