The song had been recorded previously by Albert Hammond (1972) and Phil Everly (1973), but The Hollies ’ version became the definitive hit. The Air That I Breathe (The Hollies) 1974 - Facebook
The song was written by the British-Gibraltarian duo and Mike Hazlewood shortly after they moved to Los Angeles.
Hazlewood’s contribution to the lyrics—including the title line—was inspired by the dense LA smog . He described looking at the Hollywood Hills and seeing a "yellow monster" of pollution, which led him to the idea of clean air being a basic necessity.
Hammond’s inspiration was more personal; he wrote it for a woman who gave him shelter and kindness when he was broke, lonely, and without a work permit in Los Angeles. The Hollies' Definitive Version