See the definition of “dark” fleet by Lloyd’s List
Lloyd’s List defines a tanker as part of the dark fleet if it is aged 15 years or over, anonymously
owned and/or has a corporate structure designed to obfuscate beneficial ownership discovery, solely deployed in sanctioned oil trades, and engaged in one or more of the deceptive shipping practices outlined in US State Department guidance issued in May 2020. The figures exclude tankers tracked to government-controlled shipping entities such as Russia’s Sovcomflot, or Iran’s National Iranian Tanker Co, and those already sanctioned.