Lying to fix a metropolis (9)
I believe the answer is:
mendacity
'lying' is the definition.
(thesaurus)
'fix a metropolis' is the wordplay.
'fix' becomes 'mend' ('mend' can be a synonym of 'fix'**).
'metropolis' becomes 'city' ('city' can be a synonym of 'metropolis').
'mend'+'a'+'city'='MENDACITY'
'to' acts as a link.
(Other definitions for mendacity that I've seen before include "Quality or habit of telling lies or being deceitful" , "Untruthfulness" , "Lying" .)