What's the stinkiest city in the world?

Samuel Taylor Coleridge thought that honor should go to the German city of Cologne (a.k.a. Köln ). The poet wrote:

In Köln, a town of monks and bones,
And pavement fang'd with  murderous stones,
And rags and hags, and  hideous wenches,
I counted two-and-seventy stenches,
All well defined, and several stinks!