Sometimes you can poke it about a bit and conclude that after all it doesn't belong in the world where you thought it did, so take a note and maybe use it later. A story does need unity of theme as well as clutter.
But sometimes it does seem to fit the world, and it's always useful to have some random oddities to make the world convincing, but it has to go somewhere.
Easier if the world has not been mapped out, you can add some more regions. But if you have the world, you probably have some blank spaces on the map of quite some size, but some vague notions of the sort of thing you want to go in there.
Then, if what goes in there is too uniform, it lacks realistic clutter.