The convenience and flexibility of the cloud has transformed data storage for organizations and individual users alike. But for all its convenience, the cloud adds a new complexity to the old security challenge of making sure that deleted data is actually erased. The cloud introduces an additional, more basic complication: The cloud provider, not the user, has physical custody of the data. At stake for cloud users are both compliance issues and the potential exposure of supposedly deleted data. Because organizations are responsible for their own compliance, cloud errors can expose them to sanctions.”]
Source: https://securityintelligence.com/zombie-cloud-data-what-your-delete-key-may-not-delete/