The most common and most likely answer to this crossword clue is the 8 letter word PRETORIA
I've seen this crossword clue in The Guardian
P
R
E
T
O
R
I
A
More clues leading to the result PRETORIA
- Correct to repair an African city
- Airport constructed outside European capital
- Stupid rioter in Pennsylvania capital
- African city building to repair
- Airport rebuilt outside key African city
- Capital turn of a pierrot
- African city airport given makeover, full of energy
- Prince about to broadcast back in capital
- Prepare a report about India's capital city
- Capital‘s name finally included in new airport
Buddy explains!

The straight part
We know that "Capital" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case capital = pretoria.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.