The map below shows Azure data centers in which App Services can be deployed. The icons below represent the state of the .NET Core 3.1 deployment. Click an icon for details on what's available.
You can run 3.1 in any region if you build your app in self-contained mode. See this documentation about options for deploying preview (or not-yet-fully-available) ASP.NET Core apps.
No .NET Core 3.1 requirements have been met.
The runtime and shared frameworks are there, but the .NET SDK is missing. You can run 3.1, but not build 3.1.
You can build .NET Core 3.1 apps using Kudu and run .NET Core 3.1 apps in this region.