Tonkin Delta capital (5)
I believe the answer is:
hanoi
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">tonkin delta capital</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for hanoi that I've seen before include "Vietnamese capital" , "Capital city of Vietnam" , "capital out East" , "foreign city" , "Asian capital on the Red River" .)