The most common and most likely answer to this crossword clue is the 5 letter word DELHI
D
E
L
H
I
More clues leading to the result DELHI
- Group of model Hindus found here
- City's food shop being reported
- Asian city and Greek one without parking
- Capital husband invested in food shop
- Heard about up-market food shop: it’s in India
- Capital at one time husband invested in food store
- I was in van going north touring hot capital territory
- Indian city food shop husband enters
- Once a capital food shop, we hear
- Talking shop in Asian city
Buddy explains!

The straight part
We know that "Once a capita" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case once a capita = delhi.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.