The most common and most likely answer to this crossword clue is the 13 letter word CIRCUMSTANCES
I've seen this crossword clue in The Guardian
C
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More clues leading to the result CIRCUMSTANCES
Buddy explains!

The straight part
We know that "Situation" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case situation = circumstances.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CIRCUMSTANCES mean?
CIRCUMSTANCES noun- That which attends, or relates to, or in some way affects, a fact or event; an attendant thing or state of things.
- An event; a fact; a particular incident.
- Circumlocution; detail.
- Condition in regard to worldly estate; state of property; situation; surroundings.