The most common and most likely answer to this crossword clue is the 4 plus 4 letter word ACID RAIN
I've seen this crossword clue in The Times
A
C
I
D
R
A
I
N
More clues leading to the result ACID RAIN
- Area police announced restriction that sours the air
- Account I empty - nasty fall results
- Bill has one channel for outflow — polluted showers?
- Damaging fall in account I empty
- Damaging fall in a Jersey ditch?
- Pollutant in a Jersey ditch?
- Drops environmentally unfriendly car India produced
- Precipitation from a Jersey sewer
- Cops break into a shower, which makes for a bad atmosphere
- Announced check on drug problem for the environment?
Buddy explains!

The straight part
We know that "Damaging fall" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case damaging fall = acid rain.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.