Final answer:
Megacities, defined as urban areas with over 10 million residents, have emerged out of the global trend of urbanization, especially in developing countries. Sustainable development is identified as a key challenge in supporting further urban growth without environmental damage.
Step-by-step explanation:
The concept of a megacity is closely linked to urbanization trends worldwide. Historically, urban areas have grown as economies develop, with industrialization sparking movements from rural to urban centers. Today, over 55 percent of the world's population lives in urban areas, with North America being the most urbanized region, followed by Latin America/the Caribbean and Europe. In contrast, urbanization in Africa is less pronounced, but this is rapidly changing as nations there develop. Tokyo currently holds the title as the world's most populous city, with New Delhi following close behind. The proliferation of megacities, particularly in the developing nations of Asia, Africa, and Latin America, reflects not only population growth but also economic shifts. The challenge going forward, according to the United Nations, is to embrace sustainable development practices that allow these burgeoning urban centers to flourish without compromising environmental integrity.
With the advent of megacities, the world has seen significant changes in demographic landscapes. The rise of huge urban conglomerations poses diverse sets of challenges, especially for less developed countries where urbanization often outpaces the capacity to provide adequate services and infrastructure. Going forward, ensuring sustainable development will be crucial in managing the delicate balance between urban expansion and environmental conservation.