You're a
Planisphere (world map)
Divided by a wall, N and S.
Equator, N=North, S=South
Tunnels in between, but no one pass.
Meridians connect North and South, they're imaginary lines so nobody can use them as "tunnels"
The West has more, and the East has less.
West (Europe and America) is rich, East is generally poor.
Less is more, but More is less.
This is a bit tricky, but I think the explanation is in the Mercator projection. In fact, it distorts areas and lengths: what's far from equator appears big (More) but it should be smaller (Less) and viceversa.
I have rectangular border
Maps are rectangular, usually.
What am I, can you guess?
Planisphere (world map)