In China it's due to the state wanting all of China to be at Beijing time, and for Beijing, it is standard time. As for Spain, Franco switching to German time, because he liked Hitler, and Spain never switched back. Besides, Spain observes DST like the rest of the EU. Argentina is however an example of a country that switched to permanent summer time and sticking with it (since 2009).
replyWhether we call it "permanent summer time" or "aligning with the political region to the east" it's the same thing: late sunrise, late sunset.
reply(Spain is effectively using single-double DST, based on the delta from solar)