Conclude New York is full? Like hell (10)

I believe the answer is:

infernally

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'is full? like hell' is the definition.
I can't judge whether this defines the answer.

'conclude new york' is the wordplay.
'conclude' becomes 'infer' (inferring is a kind of concluding).
'new' becomes 'n' (abbreviation as in New Testament NT).
'york' becomes 'ally' (I can't explain this - if you can you should give a lot more credence to this answer).
'infer'+'n'+'ally'='INFERNALLY'

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(Another definition for infernally that I've seen is " irritatingly so".)

I've seen this clue in The Guardian.

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