FAIR is an ideal for data (and research) and is part of the Open Science idea. FAIR Data stands for Findable, Accessible, Interoperable and Reusable.
Findability is warranted by demanding each archived data package has a DOI attached to it.
With regards to Accessibility, this depends on the nature of the data. Data packages containing personal data will in principle not be publicly accessible, but only for the researcher and/or the research group, depending on what has been agreed upon in the Informed Consent agreements.
Interoperability and Reusability (and Reproducibility) is supported by the documentation like metadata, code books, readme files and lab journal and reusability by the demand of having all data offered as Open Access (when no personal data is involved) and by using the CC BY 4.0 SA license.