Nearly all admitting India’s humid (5)
I believe the answer is:
moist
'humid' is the definition.
(I've seen this before)
'nearly all admitting india's' is the wordplay.
'nearly all' becomes 'most'.
'admitting' means one lot of letters goes inside another.
'india' becomes 'i' (phonetic alphabet: alpha, bravo, charlie etc.).
'most' going around 'i' is 'MOIST'.
(Other definitions for moist that I've seen before include "Dampish" , "Affected by tears, perhaps" , "Slightly wet, damp" , "sloppy" , "Damp or clammy" .)