Outskirts doesn't mean suburbs. Suburbs are often in the outskirts but a town with no suburbs would still have outskirts.
However, "peripheries" should definitely be accepted no? It means the same thing as outskirts but is a friendlier translation.
It says "Periferia". Isn't that singular?
Yes, it's singular, so contrary to other DL sentences (oamenii periferiilor sunt mai săraci) “periferia” here seems to mean the whole periphery of a city rather than just a quarter somewhere in the periphery.
I write suburbs and it was considered wrong. Is it so? and why? (I'm not an English native speaker, btw).
In English (England, not america) we would say suburbs,