The highest capital cities in the world (eight at over 2000m):

Sucre (Bolivia) 2783m, though seat of govt is La Paz at 3660m
Quito (Ecuador) 2763m
Thimphu (Bhutan) 2736m
Bogota (Colombia) 2619m
Asmara (Eritrea) 2363m
Addis Ababa (Ethiopia) 2362m
Sana‘a (Yemen) 2253m
Mexico City (Mexico) 2216m

Data from here. There's then quite a jump from Mexico City to the next highest, Kabul (1807m).

Having just arrived in Addis, I wondered what it was that was making me feel more tired than I expected, and also why the weather was rather cooler than I had expected for 9° north of the Equator. Now I know.

(Also I bet there is no really measurable difference in alitude between here and Asmara!)