I don't know if its internationally recognized, but Port Arthur. It's the most depressing town I have ever passed through. The skyline is nothing but refineries and every house is rotting. I drive between Baton Rouge and New Orleans regularly and that's my normal. Port Arthur is a whole other level of poverty and pollution.

https://www.vice.com/en/article/sentenced-to-death-what-its-like-living-in-a-cancer-plagued-oil-town/