As with its immediate predecessor, the Galaxy M30s, Samsung will release the M31 to the Indian market via Amazon. This site is currently teasing the phone as one that will replicate the popular "battery monster" in many ways, its 6000mAh battery included. However, its camera specs stand to improve somewhat.
https://www.notebookcheck.net/The-Samsung-Galaxy-M31-will-launch-via-Amazon-in-soon.454106.0.html