Country Is Only City
If the story is set in this country, it's most likely specifically in this location.
When a particular country (or administrative subdivision of one) is the setting of a particular story, there's a strong likelihood that it will be in one particular major city. Barring city-states like Singapore where the country is a city, there are a lot more equally-worthwhile locations in a country than just the one well-known metropolis.
A Super-Trope to New York Is Only Manhattan and Britain Is Only London. See also Tokyo Is the Center of the Universe and Eiffel Tower Effect.
