Within the overall shift toward urbanization, megacities, green cities, and smart cities are emerging as new trends. As the competition paradigm shifts from competition among countries to competition among cities, the number of megacities with populations of more than 10 million is expected to increase in the future. In addition, with a growing sense of obligation to improve the environment, the paradigm is shifting to eco-friendly cities. Through convergence of IT technologies in this sector to create added value, a transition to green cities will provide a wealth of business opportunities. Under ongoing and emerging trends, megacities, green cities, and smart cities will bring changes to steel demand.