Temporary fault makes light go out around China's capital (6)
I believe the answer is:
glitch
'temporary fault' is the definition.
(I've seen this before)
'light go out around china's capital' is the wordplay.
'go out' is an anagram indicator.
'around' is an insertion indicator.
'capital' says to take the initial letters.
The initial letter of 'chinas' is 'c'.
'light' with letters rearranged gives 'glith'.
'glith' enclosing 'c' is 'GLITCH'.
'makes' acts as a link.
(Other definitions for glitch that I've seen before include "Sudden brief malfunction in electronic system" , "Fault (electronics)" , "Flaw" , "Computer problem" , "Unexpected setback" .)