Religious people spending hour in Asian river (5)
I believe the answer is:
indus
'asian river' is the definition.
(I've seen this before)
'religious people spending hour' is the wordplay.
'religious people' becomes 'hindus' (I've seen this before).
'spending' suggests deleting specific letters (to spend can mean to give out or give away).
'hour' becomes 'h'.
'hindus' with 'h' removed is 'INDUS'.
'in' acts as a link.
(Other definitions for indus that I've seen before include "Pakistani river" , "River of Southern Asia" , "River flowing from Tibet to the Arabian Sea" , "River rising in Tibet" , "Long river of Asia" .)