When my neighborhood got invaded, it definitely got dirtier. When these “wonderful, vibrant, hardworking undocumented folks” decide they no longer want a mattress, Christmas tree, piece of furniture, or anything else, they dump it on the sidewalk. They’re fond of leaving rusty old cars in their front yards, spraying graffiti, tossing trash, etc. Look at any before-and-after pictures of an invaded area, and you will see, it’s dirtier “after.”
I particularly enjoy seeing the hundreds of dollars worth of toys and bicycles/tricycles that have been given sanctuary/amnesty on that sidewalk... not so much "dumped" as "permanently parked." Most colorful.