【明報專訊】As pointed out by the World Health Organization, urbanization is a result of population migration from rural areas in addition to natural urban demographic growth. It is a process of global scale changing the social and environmental landscape on every continent. According to the 2018 Revision of World Urbanization Prospects published by the United Nations in May 2018, 55% of the world's population live in cities. The percentage is expected to rise to 68 percent by 2050.