"Lifting a ban" — why does "lifting" mean "removing"?

Solution 1:

It's a variation on the theme of lifting a weight off someone/something. You lift the heavy load that was restraining a man and let him move faster.

Solution 2:

To my opinion, "lifting" is used here to indicate some burden is now lifted from the concerned person or thing and that thing is now free to move. Ban is a kind of burden "put over" some action to freez it. So If you wish to remove it, then you will lift it from the action.