On the other hand, Prague would be much higher if the official population number was accurate at all - since this official statistic in Czechia relies purely on the number of registered people and does no further analysis. There's over a million people more than the official number says - that's well known even to the government. Analysis of mobile device traffic and other stuff like that suggests multiple millions.

I'd definitely say it's a major EU city. Maybe even a major The West city. I agree that it's hard to compare it to places in Asia, though.