In this novel, just as in others, Dickens takes the industrialised city as his main focus and explores how the polluted, smog-filled environment has an impact on the characters that try to eke out an existence within it. Dickens in his work was sharply critical of industrialisation and the conditions of squalor and urban poverty that developed as a result. In this novel he critiques an approach to business and to employees that treats them as just cogs in a machine and profoundly dehumanises them, rather than recognising them as human beings in their own right. Note how Coketown is described in the following quotation from Book the Second, Chapter One:
Coketown lay shrouded in a haze of its own, which appeared impervious to the sun’s rays. You only knew the town was there because you knew there could have been no such sulky blotch upon the prospect without a town. A blur of soot and smoke, now confusedly tending this way, now that way, now aspiring to the vault of Heaven, now murkily creeping along the earth, as the wind rose and fell, or changed its quarter: a dense formless jumble, with sheets of cross light in it, that showed nothing but masses of darkness—Coketown in the distance was suggestive of itself, though not a brick of it could be seen.
Note how there is a contrast between the soot and smoke that fills Coketown and surrounds it like a shroud and the sun's rays. These are used to represent the moral corruption inherent in Coketown and the sun is used to represent the beauty of nature that cannot get through to Coketown. Such descriptions establish Coketown as both a place that is literally dark and full of squalor but also spiritually and metaphorically dark and devoid of human comfort as well, as indicated by the poverty of its inhabitants and the exploitation of them by the ruling class, such as Bounderby. Such presentations of the city therefore help emphasise the social critique of industrialisation that Dickens explores in this novel.
The city 'Coketown' is so prevalent an image in the novel that it almost becomes a character. It draws on the experience that Dickens had on visits to Manchester and Preston (Northern English Industrial centres) where he was moved by what he saw. His description of Coketow is a mixture of the reality of life in an industrial city in Northern England and his style of writing (his almost childlike images of the mad elephants and the soke serpents (see 'The Keynote' for more detailed description.)