San Francisco does, as does Boston, DC, and London, as far as I can tell. New York City's Chinatown takes the grand-ol'-seething-cesspool-of-stink cake for sure.
So what's the problem? Is it city oversight? Is it the sheer number of shoppers looking for those $0.89 bags of bok choy or Haw Flakes every day? Or is related the the 'broken windows' theory - if you see a piece of trash on the ground, are you less likely to want to keep the place clean yourself?
This is particularly baffling considering that Chinese families tend to keep their houses crazy clean (see: leaving your shoes by the door) and are particularly fastidious about cleaning their chopsticks, plates, and cups before eating at restaurants. I've also heard that Asians tend to like "clean" smells when it comes to perfumes and scents, more than other races.
So what gives? Any ideas?
And, related: do Asian Americans feel obligated to visit Chinatowns when traveling?