Old district welcoming approach that protects the atmosphere (5-8)

I believe the answer is:

ozone-friendly

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'approach that protects the atmosphere' is the definition.
The definition and answer are not the same part of speech.

'old district welcoming' is the wordplay.
'old' becomes 'o' (abbreviation).
'district' becomes 'zone' (synonyms).
'welcoming' becomes 'friendly' (synonyms).
'o'+'zone'+'friendly'='OZONE-FRIENDLY'

Can you help me to learn more?

(Another definition for ozone-friendly that I've seen is " (Of aerosols) green".)

I've seen this clue in The Irish Times.

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