In general, Question X is closed as a duplicate of Question Y if answers to Question Y would answer Question X (in the case where Question Y has answers). See, for instance, the help center:
Questions should be closed by casting close votes if:
- they are sufficiently similar to existing questions and would be answered identically to them.
If you ask a question about Situation A in Zimbabwe, the question may very well be different enough from a question about Situation A in the United States that your question should not be closed as a duplicate. Answers to the target won't answer the question at hand; there's no reason to close the newer one as a duplicate, for the simple reason that it isn't.
Now, we're going to have to look at things on a case-by-case basis. Perhaps the situation is such that answers would be valid to both questions - maybe the cultures are similar enough. If this is the case, then we could close one as a duplicate of the other.
The point is, though, that having the same situation doesn't imply that two questions are similar enough that one should be closed.
See also, on Meta Stack Exchange: