Public transport in need of assistance after cutting capacity (6)
I believe the answer is:
'capacity' is the definition.
(bushel is a measure of capacity)
'public transport in need of assistance after cutting' is the wordplay.
'public transport' becomes 'bus' (bus is a kind of public transport).
'in need of' says to put letters next to each other.
'assistance' becomes 'help' (synonyms).
'after cutting' means to remove the last letter.
'help' with its final letter taken off is 'hel'.
(Other definitions for bushel that I've seen before include "Imperial measure for grain" , "'Don't hide your light behind a . . . . . .'" , "Dry measure of eight gallons" , "Don't hide your light under this grain measure" , "Eight-gallon measure of capacity - under which one's light should not be hidden" .)