Google Play has been working to minimize app install fraud for several years. We have removed two apps from the Play Store because of the issue. If an app violates our policies, we will take action. We also discovered evidence of app install abuse in 3 ad network SDKs. We will continue to work to find out if any of these apps are in violation of our policies. We are happy to clarify that these apps have been removed from the app store and that they are not being used in the future.”]
Source: https://security.googleblog.com/2018/12/tackling-ads-abuse-in-apps-and-sdks.html