How does the author use symbolism in the novel, Trash?

The word for human waste, stuppa, represents the condition of the city as a corrupt place in the third-world. Since the majority of the city does not have access to modern toilets, they dispose of their waste through the trash that ends up in places like Behala. But it also points to the corruption of the city, as the rich sit on the money that could be used to provide citizens with running water and a sewage system.