Google is adding another device to the supported list of ARCore device with the OnePlus 6. This comes just a few days after they added the OnePlus 5T device to the list as well. Not only that, but other devices like the Mi 8 is also getting ARCore support.
As of now, you will not be able to download the ARCore app from the Play Store, as it still listed as not available in your country. However, some people have reported that they sideloaded the app into their supported phone and it seems to work without any issues. The app will eventually appear in the app store but as of now, we have to stick to the old method of sideloading. Google has not updated their own ARCore supported devices list as well, so we might have to wait awhile before it becomes official.