Green bus, travelling lower class (8)

I believe the answer is:

subgenre

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'lower class' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'green bus travelling' is the wordplay.
'travelling' indicates an anagram.
'green'+'bus'='greenbus'
'greenbus' is an anagram of 'SUBGENRE'.

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(Other definitions for subgenre that I've seen before include "Division of a style of art or literature" , "Literary style within a larger category" .)

I've seen this clue in The Independent.

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