As you can tell from the comments, a lot of us first heard https://www.youtube.com/watch?v=FaSKD1Bd11M in the movie "Slap Shot." And I still got the answer wrong!
I think this is a case where, if you've grown up with knowledge of Saskatoon, you've probably never associated the name with anything other than the city (or berry) itself. It took me a while to understand the clue as well.
I would agree, Istanbul would need to take Tehran's place: The 16,000,738 for Tehran is including metro area, via Wikipedia - in the "official" JetPunk list it is listed as 8,895,947 for the city proper (https://www.jetpunk.com/info/capital-cities-by-population#list-of-all-capitals-by-population), while Istanbul has 15,514,128 in that category (on Wikipedia, as it is not listed on JetPunk, as it is not a capital). If not, a clarification regarding metro area would be helpful.
I think only 40% getting Port Sudan shows the hint should maybe be worded slightly differently. Something like, “It’s the largest port. In Sudan.” Without a reference to thinking. My guess is that that wording alone would lead to over 50%.
Disagree. I got it right. Would have had a 0% chance of getting it without the winking hint, because without that, it suggests it would just be some random city name that you couldn't get if you didn't know it. Aden, Vancouver, and Jeddah are major port cities. There's no reference in their names to "Port" and if you didn't know to guess it, you'd probably just shrug and move on.
Is Tehran really in the Middle East? The region of Persia is historically, geographically, religiously, and to some extent modern geopolitically pretty separate from the Levant, Mashriq, Arabia, and North Africa (whose inclusion I also question, though Egypt is definitely more acceptable than, say, Morocco). I wonder if it's better described as part of South or Central Asia, or a separate thing entirely.
Tehran population: 16,000,378
(Especially given the nature of the clue!)
... oh, Saskatoon.