The criticism comes in form of sarcasm in the way that Dickens chooses to describe Coketown, the setting of the story, and what goes on with the people and their ways of life as a result of Coketown's extreme industralism.
We learn that Coketown is a town made of red, dirty bricks. Every single building has the same look and one is no different from the other (this is criticism towards the lack of uniqueness that comes as a result of mass production). In Coketown, people have the same schedules, come in and out at the same time from their homes and work (criticism of the effects of industralism and mass production in the lives of factory workers, making them slaves to the job). We also learn that the town completely lacks personality- some buildings might add a slight touch of awkard decoration to their buildings, and this is also criticism showing how life in the factories take away the soul and spirit of the workers due to the extreme conditions of their labor.
In Coketown, the arts are null- kids are supposed to learn facts and numbers, amounts, and quantities- this is criticism on the previous "theft of spirit" that occurs as a result of the factory life. The characters in the story, such as Louise, lives in a loveless marriage for the sake of money, and the grandiouse leaders of the industries only live for the sake of money. In all, quantity and not quality, according to Dicken's criticism are the reasons why people breathe in Coketown.
Dickens was quoted as saying that in this story, humans are viewed as products of industrialism instead of the vice versa: that we created it and industralism is a product of our hard efforts. Hence, this is an ample way to show what he meant when he came forward to expose what was happening in Victorian London