Green’s Dictionary of Slang

Smoke, the n.

also great smoke, the
[the pall of pollution that, before the clean air legislation of the 1950s, hung over the industrialized city]

1. [mid-19C+] London, as regarded from the provinces; occas. as Smoke.

2. [mid-19C+] (Aus./US) any big city.

3. [1920s-40s] (Aus.) without def. article, Melbourne.

4. [1940s+] (Aus.) Sydney, Melbourne.