You may know this. I didn't, I didn't even know it was a thing.
A post came up on Facebook explaining why airlines detour around the Tibetan plateau. It's not due to military domination or restrictions, and only partly due to turbulance over the mountains. It's because the plateau is 14,000 ft high, and if the aircraft suffered a decompression, it would not be able to descend to the safe level of 10,000 ft. Besides, there are no suitable airfields to make an emergency landing.