3. The population of Ha Noi city is fewer than Hồ Chí Minh city.
4. The area of HCM city is smaller than Ha Noi city.
5. The weather in Ha Noi is colder than in HCM city.
6. The population of HCM city is more than Ha Noi city.
7. The area of Ha Noi city is larger than HCM city.
8. The weather in HCM city is warmer than in Ha Noi city
9. The pollution density in Ha Noi is less than in Hồ Chí Minh city