Polluted pool I abandoned (9)

I believe the answer is:

tarnished

'polluted' is the definition.
(tarnished can mean dirtied or stained)

'pool i abandoned' is the wordplay.
'pool' becomes 'tarn' (I've seen this in another clue).
'abandoned' becomes 'shed' (shed can mean to abandon or cast off).
'tarn'+'i'+'shed'='TARNISHED'

(Other definitions for tarnished that I've seen before include "Sullied" , "Stained" , "Dulled, discoloured" , "Blemished" , "Having lost lustre" .)

I've seen this clue in The Times.

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