The game had initially launched in Australia and New Zealand, as is usually the case when apps begin rolling out around the world. It later made its way to the US and last we heard, it was available in the UK. Unfortunately for the rest of the world, we’re still waiting for the app to be released.
Just yesterday Niantic released a statement regarding the app’s availability in SEA in which basically they stated that gamers would have to wait. The game was initially planned for a speedy worldwide release but due to server issues, presumably since they did not expect it to be so popular, they had to halt its international rollout.
We can only assume that the game’s slow but steady rollout now is because Niantic wants to ensure that when the game is launched it does not have any adverse side effects for other gamers. In the meantime keep checking back with us as we’ll keep you guys up to date.