  Smart city technology is making cities more effective which is necessary for
the rapid growth in urban population. With the rapid increase in advanced
metering infrastructure and other digital technologies, Smart cities have
become smarter with efficient electronic devices and embedded sensors based on
the Internet of Things (IoT). This paper provides a comprehensive review of the
smart cities concept with its components and applications. Moreover,
technologies of IoT used in smart cities infrastructure and some practically
implemented smart cities in the world are mentioned as exemplary
implementations. Some open issues and future directions concluded the paper.
