This caused the construction of gigantic buildings where too large masses of human beings are crowded together
In the attributive clause after 'where' above, is 'crowded' the past participal of the action verb 'crowd' (i.e., a passive tense) or is it an adjective to describe the state of human beings?
I tend to think it is a passive tense to stress the action as people do not have any active roles in the context of the article (i.e., the impact of industralizaiton on our society).