Go pale, affected in crowded city (6)
I believe the answer is:
whiten
'go pale' is the definition.
(I've seen this in another clue)
'affected in crowded city' is the wordplay.
'affected' becomes 'hit' (I've seen this in another clue).
'in' means one lot of letters goes inside another.
'crowded city' becomes 'wen' (historical term for a large city. I am not sure about the 'crowded' bit.).
'hit' placed into 'wen' is 'WHITEN'.
Can you help me to learn more?
(Other definitions for whiten that I've seen before include "Bleach" , "Become less colourful" , "Turn pale" , "Blanch" , "free from guilt" .)