In the 1990s, all the cities were conventional cities because at that time there was no concept of the Internet. In the last decade, the concept of smart city has been spread all over the world with the advancement of Internet, and it puts an impact on both small and large cities. In the present scenario, the urban areas affected by various problems and smart cities are only the solutions. The definition of smart cities depends on the word of "smart," which means a digital city, intelligent city, and sustainable city. The basic concept of the smart cities is that the city should be "green," more "accessible," and more "liveable." This chapter explores the changes made in the conventional cities to become the smart cities, which helps to improve the lifestyle of city people and reduce waste and pollution.