AdAway is an open source application for Android that gives users a way to block ads in the operating system and Internet browsers. Read more about AdAway  

One of the most pressing problems for people that are browsing the Internet on their phones or tablets is the traffic that’s being lost on ads, not to mention the potential slowdowns of the devices themselves.
One of the ways to fix this problem is with an Adblock app, but that’s not really allowed on Android devices. All applications that try to block ads are not allowed in the official store, and they also require root access.
The same is true for AdAway which uses a very effective way of dealing with the app, by using hostfiles. The only drawback is that it requires root access to properly work. Of course, users can also define hostfiles in the Blacklist, and it’s possible to add any other hostname or IP in the Redirection list.