The most common and most likely answer to this crossword clue is the 9 letter word HOARDINGS
I've seen this crossword clue in The Times
H
O
A
R
D
I
N
G
S
Buddy explains!

The straight part
We know that "commercial areas" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case commercial areas = hoardings.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 HOARDINGS mean?
HOARDINGS noun- A temporary fence-like structure built around building work to add security and prevent accidents to the public.
- A roofed wooden shield placed over the battlements of a castle and projecting from them.
- A billboard.