The first thing if you ask somebody, what is a smart city, there can be multiple answers to the above question. It means different things to different people. The conceptualization of smart city might vary from city to city, and country to country depending on the level of development, willingness to change and reform, resources available and aspirations of city residents.
But to a layman it can be the city which accommodate the changes as desired by the changing requirements of infrastructure, transport, safety and civic solutions, and to provide the citizens of that city innovative solutions, which can make his life easy.
Even urban planners aim at developing the entire eco-system, which is represented by four pillars of comprehensive development- institutional, physical, social and economic. All these are long term goals, and cities work towards developing such comprehensive infrastructure incrementally, adding of layers of smartness.