Arrow: Starling City was like this before Oliver returned to set things right. Most of the city was controlled by corrupt businessmen, a lot of the most beloved people in the city were also horribly corrupt (just better at hiding it), and the Glades were basically a third-world country. The Arrow and his team improved things by taking out major power players and cleaning up the streets, but the various supervillains who keep nearly destroying the city repeatedly complicate their attempts to improve things.
Batwoman (2019): Just like almost every depiction of Gotham in any other media, be it comics or other adaptations. However, this Gotham is actually worse than usual, since Batman has been missing for years and Wayne Enterprises has collapsed in his absence. This is even used as the excuse for its previous Writing Around Trademarks treatment in the 'verse, as the place is such a hellhole no one ever wants to even talk about it. The rich travel in armored jeeps and have heavily armed escorts while shopping, any newcomers are mugged by thugs with military hardware, and while the cops aren't actively violent against prisoners, they are aggressively apathetic.
Channel Zero: The Butcher's Block neighborhood of the city of Garret is a sacrifice zone which is completely rundown, with little-to-no infrastructure or police input, with criminals and crazy people all over the place. And that's not even getting into the Cannibal Clan of Axe-Crazy murderers running around abducting and eating people.
Deadwood: Deadwood itself. Eventually gets a telegraph, employs a sheriff and elects a mayor. Remains a place where the preferred way of getting rid of inconvenient corpses is by feeding them to Mr. Wu's pigs.
Game of Thrones: Quite a lot of King's Landing in the Crownlands can be said to be this underneath some lovely or even outright stunning architecture, in a Stepford Smiler kind of way. Flea Bottom, however, doesn't try masking what it is, at all.
The eponymous city on Gotham is this by definition. When the mob controls the cops, you know things are going to be ugly. Of course this is to help tie it into the Batman mythos.
Justified: Harlan County is the rural version. The sheriff's department is on the take, the economy depressed, and the when it comes to employment the choice is between criminal gangs and families like the Crowders and the Crowes, or the brutally oppressive Black Pike mining company. The Miami cartel, the Detroit Mob, and the latter's Dixie Mafia subsidiary all have their tentacles in the region, further worsening the violence and the crime rate, as different factions within them jockey with each other and local criminals for control of the county. That's not even mentioning the town of Bennett, which is ruled by the eponymous Bennett clan, who use the town as a front for their marijuana operation, or Noble's Holler, an all-black community that keeps their racist white neighbors at bay by playing the rest of the county's gangsters off against one another. We've yet to meet anyone from Harlan who isn't caught up in illegal activity of one sort or another, and the efforts of the protagonists seem to do little beyond creating swiftly filled power vacuums.
Masters of Horror: In "Imprint", the remote island is "only inhabited by demons and whores".
Revolution: All cities are apparently like this now: "If you were smart, you left the city. If you weren't, you died there."
The town of Riverdale. In season one it was depicted as a quiet small town rocked by the shocking murder of maple syrup heir Jason Blossom. From season two onward it has become an epicenter of organized crime, supports multiple gangs, has serial killers, cults, rioting in the streets, been quarantined for weeks... In-universe all of this has happened within about a year and half, which is the fastest community decline you would see outside of a war zone!
Trailer Park Boys: Sunnyvale trailer park Nova Scotia, a mockumentary about three career criminal conmen, and their kin. This property is supervised by a drunk deranged discharged cop and his dimwitted obese underling. Overrun with feral children who randomly throw bottles at residences, and 3 career criminals who naturally cause hilarious hell during the course of the season which revolves around that seasons "Big Dirty" (career heist).
The Wire: Averted Trope. While the lion's share of the show takes place in neighborhoods of Baltimore where everyone is either a drug dealer or a drug addict, the show takes time out to illustrate there are nice parts of Baltimore. Further, it takes a close and careful look at how such disparate places can be so close together and yet so far apart. As Bubbles says when riding with McNulty in season 1, "Thin line 'tween heaven and here."
In season 3, Major Colvin's "Hamsterdam" - a project wherein he essentially legalizes drug usage in three designated areas in the Western District - shows what happens when you concentrate all West Baltimore crime in one place.
In the season 4 premiere, a lecturer is giving a presentation to Western District cops on counterterrorism. Santangelo isn't too impressed by the lecturer, eventually interrupting to say, "No disrespect to your appendix, but if them terrorists do fuck up the Western, could anybody even tell?" which draws laughter from the other cops as they take their turns poking jabs at the counterproductiveness of counterterrorism training in their district.