Why does China have one time zone and Russia have eleven?

Time zones follow lines of longitude in principle, with each 15 degrees representing an hour, but every country sets its own by law and many depart substantially from the astronomical arrangement. China spans roughly five geographic time zones and observes a single national time aligned to Beijing, a decision made in 1949 for national unity and administrative simplicity. The practical effect in the far western region of Xinjiang is that official sunrise in winter can fall around 10am, and many residents informally operate on a local time two hours behind the official clock, producing a parallel unofficial schedule.

Russia, spanning about 170 degrees of longitude, uses eleven time zones, which is the largest number for any country and reflects a decision to keep clocks roughly aligned with the sun across an enormous territory. The number has changed repeatedly through the post-Soviet period as regions were shifted for political and economic reasons. France, counting its overseas territories, actually observes more distinct zones than any other country.

Several other departures are worth knowing. Some places use offsets that are not whole hours: India runs at UTC plus 5:30, Nepal at plus 5:45, and parts of Australia at plus 9:30, chosen to split the difference across a country's width or to distinguish national identity. Spain sits geographically in line with Britain but observes Central European Time, a legacy of a wartime alignment with Germany that was never reversed, which is part of why Spanish daily schedules run so late relative to neighbors. And the international date line bends substantially from the 180th meridian so that island nations can share a single date. The pattern across all of these is the same: what looks like a physical system is a set of political choices layered on top of one.