Unfortunately, this is not possible at this time, because Stadia needs server blades relatively close to you to provide a proper experience.
I don't know when these servers will be built near you, let alone world wide. These servers are expensive, and as such it might be a while before it becomes available word wide.
-- Baldy
I am no Google official. My messages and opinions are my own, and should not be used to judge Google or their products. Silver and gold Guides are independent volunteers that like to help out on the forums.