Where I live on the west-coast of Canada, alleys are dirty and disgusting. Most people don't go into the alleys. I think this is common is a lot of cities in Canada and the U.S.

In Korea however, alleys tend to be clean and utilized.

Here is a photo of a Korean alley in Hapjeong (합정) in the Gangbuk (강북) area in Seoul in Korea from October 2019: