Aaron10 no he's not wrong. When talking about a high population density in Geography, it's either Calcutta or Hong Kong and he chose Hong Kong. It's no problem. No Jack, you would not lose any marks - if you described the reasons / problems correctly that is.
Developing- Kolkata India
So which means Kolkata India is developing word. If u say Hong Kong, you will get definitely no marks because Hong Kong is not developing world. U will lost 10 marks!!!!!