The noisiest city I have been to is Athens–at least what I remember. I’m basing this on a fuzzy memory of an experience crammed onto a bus thinking that the people around me were angry, bit finally decided that they were having a chat and had to raise their voices to be heard above the din of the traffic. That was one bustling place, and I’ve lived in New Delhi.
There’s an article in the New York Times about how noisy Cairo is these days. It’s so noisy with horn honking and teaming people, as a matter of fact, that it’s like living in a factory. If you know anyone who has worked around machinery for a lifetime, think about how often the word “WHAT?!” comes up. Just a tad.