China is geographically wide enough to span almost five standard time zones, from roughly UTC+5 to UTC+9, yet the entire country — from Shanghai in the east to Kashgar in the far west — runs on a single official time, China Standard Time (UTC+8).
The history behind the decision
China actually used five separate time zones for part of the 20th century. The switch to a single national time zone happened in 1949, when the newly formed government sought to project national unity, and a unified clock was seen as one small but symbolic way to do that.
What this means in far western China
In regions like Xinjiang, near China's western border, official Beijing time can mean the sun doesn't rise until well into the morning and doesn't set until quite late in the evening by the clock. As a practical workaround, many people and businesses in Xinjiang informally follow an unofficial local time roughly two hours behind Beijing time, shifting their daily schedule to better match actual daylight, even though Beijing time remains the only officially recognized standard.
How this compares to other large countries
Russia, the United States, and Canada — all similarly vast — instead use multiple official time zones to keep clock time closer to local solar time. China's choice to stick with one zone despite its size makes it a frequently cited example in discussions about the tradeoffs between administrative simplicity and practical daylight alignment.
The takeaway
China's single time zone is a reminder that time zone boundaries are ultimately political decisions, not purely geographic necessities — a country can choose unity and simplicity over a closer match to the sun, and simply live with (or informally work around) the daylight mismatch that results.