Asia is the world's most populated continent, with 60 per cent of the global population. This has led to unique population policies in China and Singapore.
In many areas of Asia there is rural-to-urban migration. China has seen rapid urbanisation as an increasing proportion of people live in urban areas. Over the last 20 years, the percentage of people who live in cities has increased from 20 per cent to nearly 50 per cent. The reasons for rural to urban migration are:
In some areas, such as Shanghai, the birth rate is below replacement level. Therefore, the city's population would be shrinking. However, because of migration, the size of the city is increasing rapidly.