Vital force falls back having secured India (6)
I believe the answer is:
spirit
'vital force' is the definition.
(thesaurus)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for spirit that I've seen before include "The sort of drink" , "Courage, energy" , "Soul - ethos" , "Life-giving force" , "Gusto" .)