Power cut around middle of April creates indignation (7)
I believe the answer is:
outrage
'indignation' is the definition.
(outrage can mean indignation or fury)
'power cut around middle of april' is the wordplay.
'power cut' becomes 'outage' (an outage is a loss of power).
'around' is an insertion indicator.
'middle of' means to look at the middle letters.
The centre of 'april' is 'r'.
'outage' enclosing 'r' is 'OUTRAGE'.
'creates' acts as a link.
(Other definitions for outrage that I've seen before include "Shock horror!" , "Act that shocks public opinion, generates anger" , "Gross offence" , "Gross violation of decency" , "Deplorable insult" .)