There are no restrictions built-in to the integration of BigBlueButton into Canvas. However, the two regions you mention -- China and the UAE -- are problematic. China has it's firewall, and so does UAE (which specifically blocks VoIP).
In both cases, a student/instructor could use a VPN to try and circumvent the firewall, but that puts a lot of onus on the user.
As a half-way solution, may be possible to host BigBlueButton servers in both of those regions, but they would only be useful for students and teacher in that specific region. However, users external to those regions wouldn't be able to join the session. That would not be ideal. Logistically and pragmatically, that presents challenges for support -- especially for external users who may not understand the nuances of the restrictions and simply ask "Why doesn't this work for everyone?".
Our goal is for BigBlueButton to work for everyone. And, from our experience, BigBlueButton works well in other places that are not restricted by firewalls, but the above two are problematic.
Regards,... Fred