Deepest point in Mahanadi river (5)
I believe the answer is:
nadir
'deepest point' is the definition.
(I've seen this before)
'in mahanadi river' is the wordplay.
'in' indicates the answer is hidden within the clue.
'NADIR' can be found hidden inside 'mahanadi river'.
(Other definitions for nadir that I've seen before include "Low-water mark" , "extremely low position" , "All-time low" , "most unsuccessful point" , "Point of greatest despair" .)