Google announced that it took down hundreds of apps from its official Play Store for violating its ads policy. As the official blog notes, nearly 600 apps have been removed from the Google Play Store and banned from ad monetisation platforms, Google AdMob and Google Ad Manager, over mobile ad fraud. These bad apps displayed 'out-of-context' disruptive ads to users in unexpected ways, including impairing the usability of device functions. Google developed a machine-learning based approach to detect when apps show out-of-context ads.