Article amongst electrics is going into decline (9)
I believe the answer is:
Here is my best explanation:
'going into decline' is the definition.
'article amongst electrics' is the subsidiary indication.
'article' becomes 'the' (I've seen this before).
'amongst' indicates putting letters inside (I've seen this in other clues).
'electrics' becomes 'wiring' (I've seen this before).
'the' going inside 'wiring' is 'withering'.
'is' is the link.
(Other definitions for withering that I've seen before include "Supercilious" and "Devastating".)