Mark the urban area where there's shortage (8)
I believe the answer is:
scarcity
'shortage' is the definition.
(I've seen this before)
'mark the urban area' is the wordplay.
'mark' becomes 'scar' (mark left by an injury).
'the urban area' becomes 'city' (city is a type of urban area).
'scar'+'city'='SCARCITY'
'where there's' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for scarcity that I've seen before include "Something uncommon" , "Want" , "Shortness of supply" , "Lack - dearth" , "Poverty" .)