How to look up historical time zones by date and location

[luofeiyu]

http://www.thefreedictionary.com/time+zone

time zone Any of the 24 divisions of the Earth's surface used to 
determine the local time for any given locality.
Each zone is roughly 15° of longitude in width, with local variations 
for economic and political convenience.
Local time is one hour ahead for each time zone as one travels east and 
one hour behind for each time zone as one travels west.

Urumqi  's localtime is beijin time ,it is decided  by law .
Urumqi  's timezone is east 6 ,it is decided by geography.

There is only one localtime in all over the chian,beijin time,but there 
are 5  timezone time in china .

you are totally wrong ,not me .