No way is Hargeisa 1.2 million, same for Bosaso, 600,000 is way too high. What exactly are you basing your numbers off? Somali tabloids or is the equally ridiculous wikipedia.
the real numbers are close to
xamar-1,2m
hargeisa=1m
bosaso= 400k
burco=350k
Again where are you getting these numbers from, because it sounds like they are straight from wikipedia. A quick glance at google map will tell you that Burco and Bosaso cannot be 400k ( and i doesnt matter how many people are cramped into each bedroom).
UNDP carried out their own study and estimated Mogadishu as 900,000. Hargeisa as 560,000 and Bosaso as 164,000. Now these are obviously nowhere near accurate but to jump from 560,000 to 1,000,000 is madness.