Most of this growth is expecting to be concentrated in just a handful of countries. Of the 4.2 billion, Asia accounts for 54% of urban dwellers, followed by Europe and Africa, with 13% each.
North America now has the most urbanized regions (with 82 per cent of its population living in urban areas in 2018), while the corresponding figure for Latin America and the Caribbean is 81 per cent, followed by Europe (74 per cent) and Oceania (68 per cent).
In related news, cities like Nagasaki and Busan have experienced a significant decline in their population since the start of the 21st century.
Megacities are those with more than 10 million inhabitants and the reports says majority would be in developing countries. Several cities in countries of Eastern Europe, such as Poland, Romania, the Russian Federation and Ukraine, have lost population since 2000 as well.
The report also projected that the world's population itself will peak in a few years and decline by 2050. The report by the UN's population division goes on to say that while the global rural population will steadily increase and reach its apogee in a few years, the trend will decline by 2050.
The Guardian reports that while Tokyo is the world's largest city as of now with a population of 37 million people, Delhi follows behind with 29 million residents.
The report also estimates that by 2030, the world could have 43 so-called megacities (up from 31 today, according to reports) - those with more than 10 million inhabitants - majority in developing countries.
Mexico City and São Paulo, come next; each with around 22 million inhabitants.
The growth is caused by an accelerating shift from rural to urban living across the world, particularly in Asia, which despite hosting some of the world's largest cities has lagged behind other parts of the world in terms of overall urbanization.
The chairman of NPC, Eze Duruiheoma, stated this in NY while delivering Nigeria's statement on sustainable cities, human mobility and worldwide migration at the 51st session of commission on population and development.
As the world continues to urbanize, sustainable development depends increasingly on the successful management of urban growth, especially in low-income and lower-middle-income countries where the pace of urbanization is projected to be the fastest.
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 health care.
The report recommends governments adopt better integrated policies on infrastructure and social services to improve the lives of urban and rural dwellers.
UN DESA's Population Division is has been issuing reports on urbanization since 1988.