"a seedy district"
"the seamy side of life"
"sleazy characters hanging around casinos"
"sleazy storefronts with...dirt on the walls"
"the sordid details of his orgies stank under his very nostrils"
"the squalid atmosphere of intrigue and betrayal"

"a flyblown bar on the edge of town"
"a squalid overcrowded apartment in the poorest part of town"
"squalid living conditions"
"sordid shantytowns"