The Permanent Embargo on Technology Transfers to Immature Civilizations Act was an act passed by a significant margin of the Grand Moot of Vissia Prime in order to ban giving technology to other cultures, specifically Earth. The act was passed as a result of Jonathan Archer's request for Vissia to enter the Earth-Romulan War. (ENT - The Romulan War novel: To Brave the Storm)
Following the debacle with the Partnership of Civilizations, in January, 2166, the Xyrillians decided to retreat from membership negotiations with the Federation and joined the Vissian's embargo as a formal signatory. (ENT - Rise of the Federation novel: Patterns of Interference)