Change GAE application location
Currently it is not possible to create an App in the Asia region or migrate app after its creation. Apps can only be created in the US and Europe. Europe App creation is reserved for Premier accounts and accounts whitelisted as per 1.
If you really require to host an App in the Asia region, you can consider hosting it on GCE, however you’ll lose automated scaling. You may also have a look at Managed VM’s at [2] in case you need to use Service APIs, however keep in mind it is a new feature that is in Limited Preview and not yet recommended for production use.
1 - https://developers.google.com/appengine/docs/premier/#location
[2] - https://developers.google.com/appengine/docs/managed-vms/
Update: No whitelist is currently necessary for projects created via the new developers console. App location change is still not possible, hence it's necessary to migrate the data (e.g. Datastore admin for Datastore) and deploy to a new app. Update2: Can create apps in Asia now. Location change still unavailable. Autoscaling on GCE possible.