Google announced that app submissions to Google Play, which until recently were characterized by a short review process, are now being reviewed by an internal "team of experts" who are responsible for verifying the apps’ compliance with Google's policies. Google explains the new process by the need to "better protect the community and improve the app catalog".
The reviewers will provide developers with detailed information regarding their submission status. For instance, developers will now be informed as to the reasons why their product was rejected or suspended. In this regard, they will be able to easily fix violations of policies and resubmit their apps to Google Play.
Although the new reviewing process is likely to delay submissions to Google Play, Google has stated  that there will be no noticeable change for developers during the process. In fact, Google notes that the expert reviewers have already started operating a couple of months ago, despite the fact that apps are still being published to Google Play a few hours after the first pre-reviewed submission.
Furthermore, Google has introduced a new age-based ranking system on Google Play, which aims to help developers better label their apps for the right audience, consistent with industry best standards and world-wide convention ratings. Starting in May, developers will be obligated to complete  a ranking questionnaire for each new app or app update before they can publish it on Google Play (these questionnaires will later be reviewed by Google, ahead of submission, to verify their contents). A new app submission or an app update, which will not be accompanied by a ranking questionnaire, will be marked as "Unrated" and will be blocked in certain territories or for specific users.