When flying over high terrain, one executes am emergency descent to a safe altitude such as the MEA
That goes without saying. I assume that the poster was looking for a strategy pertaining to a specific route.
This would be similar to the terrain issue in the Contiguous 48 states - East to West. I can't recall the exact position, but there is a point - due to the Rocky Mountains - where "Drift Down / Depressurization" requires a 180 turn, and another point where continue forward is the only option.
The example I used - India / Singapore - involves a 180 turn back to a specific waypoint, then a low level airway around the terrain to a diversion alternate (Note: it's an ETOPS route). If I had the route manual in front of me, I could provide the points for better clarity, but I don't have it handy.
Nonetheless, I assume that this is the type of information he/she is looking for. Hopefully, the poster will confirm.