Not sure if it were the case here, but here in my country the slum would look like that because there is no organized garbage disposal in the neighborhood, so everyone is simply dumping their trash whenever convenient and burn them later. I mean, you could pick up a shovel and clean up the front of your house, but where would you throw those trash you just shoveled if there is no garbageman picking up trash every week? Chance that you'll just dump them across the street and burn it and the wind will pick up some bits of trash and spreading them again throughout the neighborhood, completing the cycle.
