The way it's written, it's supposed to apply equally everywhere. Think of it as a "common knowledge" sort of skill, covering things that you might learn from just walking around any town.
Even if that doesn't make a ton of sense, they need it to be that way for game purposes. It's kind of like how Religion is just one knowledge skill, and a priest of Sarenrae know exactly as much about his own goddess as he knows about Urgathoa and Kurgess.