> My understanding, from speaking to people who have stayed in the region,
> is that the distinction is highly ethnic and linguistic (Han/non-Han).

A proposal some years back: given the two languages involved, have two zones, each named for the (distinct) English-language translation of the involved language's name for the zone's most populous city. The reaction at the time was that doing so would exacerbate political tensions in the region, so the proposal was not acted on. It may be that times have changed in this regard.

     @dashdashado
 

On Sun, Jan 1, 2017 at 6:12 AM, Sanjeev Gupta <ghane0@gmail.com> wrote:

On Sun, Jan 1, 2017 at 6:54 PM, Paul Eggert <eggert@cs.ucla.edu> wrote:
Currently the commentary for Asia/Urumqi says that it covers "Xinjiang time, used by many in western China". Some people in western China use +06, some use +08 (Asia/Shanghai in our database), and the geographical boundary between the two sets of uses is indistinct.

My understanding, from speaking to people who have stayed in the region, is that the distinction is highly ethnic and linguistic (Han/non-Han).  People are aware of both time zones, and choose either +0800 or not if they are speaking Mandarin, or not.  Hotel receptionists will, when speaking to foreign guests, explicitly specify timezone, as will local business contacts.  There is no real geographical line here.

May I refer you to: https://en.wikipedia.org/wiki/The_City_%26_the_City ?