... still producing interference (6)
I believe the answer is:
static
This clue is a double definition.
'still' is the first definition.
(static can mean still or not moving)
'interference' is the second definition.
(I know that static is a type of interference)
'producing' acts as a link.
(Other definitions for static that I've seen before include "Stationary" , "Not moving or changing" , "Inactive or inert" , "showing no signs of going anywhere" , "That's shocking!" .)