Although China is shown as 1 time zone effectively it's 2 or 3 time zones. Otherwise you could cross the border into Afghanistan and have to turn your watch back 4.5 hours! Most countries adjust their times to 1hour slots and sometimes, as in Australia, 1/2 slots. I think Nepal is the only country to adjust their time to 20minutes off the hour.
Incidentally Ethiopia work off a completely different system...6am is the first hour of the day.
Sorry....when I see maps I tend to geek out a bit.