Clogged (9)
I believe the answer is:
congested
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">clogged</span>' is the definition.<br/ ><span class="explanation-format__explanation">('congest' can be a synonym of 'clog')</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for congested that I've seen before include "Clogged up" , "Overcrowded, too full" .)