MIUI 12 firmware for owners of the Redmi Note 8 Pro in India has been restricted to official testers who were part of the Mi Pilot program so far. However, it appears that Xiaomi is expecting the testing period to be completed soon, as the MIUI 12 India ROM should start rolling out "shortly".
https://www.notebookcheck.net/MIUI-12-India-ROM-for-the-Redmi-Note-8-Pro-will-be-released-shortly-according-to-Xiaomi.480284.0.html