I'm surprised that so many get hung up on the word world.
Of cos it is a world wide race in a sense but there is one thing more important than World and it is Race.
For god sake use some tiny ammount of brain capacity and understand the meaning of context.
Only regions playing under more or less the same conditions are allowed in that sense which rule out China by a mile.
Yea US realms open a few hours before EU yada yada now compare that to having twice the ammount of lockouts among other things.
The term world first was born long before most of current regions of the world even had access to the game, more or less US/EU.