Oh no I'm not saying pollution and trash are a good thing. I'm talking more about the characters. I don't buy into the idea that people (or monsters etc) have to look all perfect and colorful all the time. People don't have to look nice to be nice. And just because someone looks friendly, doesn't mean they are. Ugly can be beautiful too; Sesame Street has always supported this message.
However, while we're on the subject of how the street looks. Again, I'm not saying pollution is a positive attribute. But I think it was better when SS looked a bit more realistic, lived in. There were older skits where the characters learned how important it was to pick up trash. That's something for kids to learn in their own world.