Even though the whole poem could be interpreted as illustrating the process by which industries set in a town and tear nature appart, the most symbolic lines in the poems to represent this themes of barrenness and emptiness of modern life are
It took dominion everywhere.
The jar was gray and bare.
In the first line we can notice the influence the jar, metaphorically representing industralization, has on its surroundings and in the second line that influence is negatively defined. 'Gray' and 'Bare' refer respectively to barrenness and emptiness, which are, in turn, characteristics of modern lifestyles.