population 0 - refers to a small town that has less than 100 full time residents. It implies no one really lives there. It is used to denote that no one would ever want to either.
Friend One: Hey why don't we go cruising through La Crosse?
Friend Two: Why would you want to do that? There's nothing to do there. What is it, like population 0 or something?
Friend One: Even better no cops to catch me when I speed around the curves!