The .bio gTLD is unrestricted unless you are involved in production, transformers and retailers or otherwise involved in the field of agriculture, food and farming. In that case you will need to apply for and display the “BIO Trust Seal” provided by the registry and abide by the Principles of Organic Agriculture as outlined by the registry and IFOAM .

Some domain names may be permanently or temporarily reserved or restricted for registry operations, as premium domain names or to comply with ICANN requirements.

To comply with ICANN requirements, all two-character domains shall be initially reserved, however may be released in the future. In addition reserved names for a) International Olympic Committee, b) International Red Cross and Red Crescent Movement, and c) Intergovernmental Organizations, for new gTLDs., are not available in accordance with ICANN. The list of these names can be found here.