The song was written about Salford, Greater Manchester, England, the city where MacColl was born and brought up. It was originally composed for an interlude to cover an awkward scene change in his 1949 play Landscape with Chimneys, set in a North of England industrial town, but with the growing popularity of folk music the song became a standard. The first verse refers to the Gasworks croft, which was a piece of open land adjacent to the Gasworks 53°28′50″N 2°16′36″W / 53.4806°N 2.2768°W / 53.4806; -2.2768, and then speaks of the old canal, which was the Manchester Bolton & Bury Canal. The line in the original version about smelling a spring on “the Salford wind” is sometimes sung as “the sulphured wind”. But in any case, most singers tend to drop the Salford reference altogether, in favour of calling the wind “smoky”.

Notable renditions of the song include:

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Wikipedia