May 16 (UPI) -- Two-thirds of the world's population will live in urban areas by 2050, a United Nations report on sustainable urban planning said Wednesday.
The Revision of World Urbanization Prospects report, by the U.N. Department of Economic and Social Affairs, says 35 percent of the projected growth of the world's urban population between 2018 and 2050 will be in only a few countries -- notably China, India and Nigeria.
Asia and Africa will account for 90 percent of the increase in urban population, the report said.
The report adds that the world will have 43 "megacities," or urban areas with a population over 10 million, by 2050. It currently has 31, led by metropolitan Tokyo with 37 million inhabitants.
The study predicts New Delhi, India, now second on the most-populated list with 29 million people, will be the world's largest city by 2028.
Fifty-five percent of all people on Earth live in urban areas.
The U.N. report adds that the expected increase to 68 percent by 2050 will place extra demands on resources and services.
"Many countries will face challenges in meeting the needs of their growing urban populations, including for housing, transportation, energy systems and other infrastructure; as well as for employment and basic services such as education and healthcare," it noted.
The report recommends governments adopt better integrated policies on infrastructure and social services to improve the lives of urban and rural dwellers.