Sharp decline in poverty (8)
I believe the answer is:
shortage
'poverty' is the definition.
(thesaurus)
'sharp decline' is the wordplay.
'sharp' becomes 'short' (I can't justify this - if you can you should give a lot more credence to this answer).
'decline' becomes 'age' (get older).
'short'+'age'='SHORTAGE'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for shortage that I've seen before include "Horse tag (anag.)" , "Scarcity" , "Want" , "Dearth, lack" , "Insufficiency" .)