He continues..."Then some busybody invents electricity...the fog lifts, the world sees us as we are, and worse still we see ourselves as we are. It was a carnival ball which when the guests were unmasked at midnight was found to be composed entirely of imposters."
Waugh wrote this as parody, but it reflects the very real smogs, or "pea-soupers", which affected Victorian London. Wikipedia tells us that London had been known for smog since Roman times, and coal fires were banned (briefly) as early as 1306 (by Edward I), to try to combat the problem of pollution in the capital.
However, it was not until the 1956 'Clean Air Act' that followed the Great Smog of 1952, which darkened the streets of London and killed as many as 4,000 people over 4 days, that real action was taken to combat the problem.
Nowadays, though vehicle pollution is still a problem, there is much less pollution in London. And to experience London as millions did over 600 years you must wait for a cold day when conditions are right and the fog hangs low over the city.
So next time it happens, don't complain. Embrace the London which has long since passed and see London as it was designed to be seen: grey and smoggy.
For more about London's worst smog, the Great Smog of 1952, see the relevant page on Wikipedia.