this is more of a dirty, man made object, but it doesn't seem to convey a decaying city to me.

Hard to judge. Relevance is a challenge.... is the message that smoking is a part of urban decay? The container itself does seem in decent shape, so I would not consider it in itself urban decay. Is it an anti-smoking statement? I am just not sure what the intent is and hence nor the relevance. I think the impact is very strong, and the composition is attractive photographically.