What makes Angular the most popular web application framework?

Web & Mobile Development
Though Angular was introduced as a web application framework, it is now used to develop Android and iOS applications as well with the help of ionic framework i.e. if you have created a web application using Angular, you can use the same code to create Android and iOS mobile apps with the help of ionic.
Scalability and High Performance
Angular was designed to manage the complexity of Google’s scale. Its architecture and tool set make scaling applications a breeze for application developers. Google engineers applied top notch technologies such as Ahead of Time Compilation (AOT), Lazy loading, Server side rendering etc to make it a high performance framework.
Long term support of Google
Angular is Google’s brainchild, developed by two of its most renowned engineers. It is backed by Google’s long term support which makes it reliable for application developers. Launch of new releases of Angular every six months shows how committed Google's team is to Angular.