The controversy around Chinese swimmer Sun Yang took another twist when a Swiss court upheld his appeal against a doping ban that would have seen him serve eight years and effectively end his swimming career. Given a career lifeline by Wednesday’s ruling, Sun remains a polarising figure within the swimming community having been plagued by allegations of illegal substance use dating back to 2014. The Swiss ruling comes at a peculiar time , two days before the Christmas holiday, and the explanation for the about-face has yet to be made public leading to speculation about why the appeal was upheld. So what happened and what is next for Sun? What led to this verdict? The World Anti-Doping Agency broke the news that a Swiss court overturned the ban for anti-doping offences against Sun on Wednesday and ordered the case back to the Court of Arbitration for Sport, but with a different chairman on the judges’ panel. In February, CAS found the three-time Olympic champion guilty of refusing to cooperate with sample collectors during a visit to his home in September 2018. Wada brought the case to CAS after world swimming governing body Fina had issued Sun with just a warning. Italian judge in Sun Yang CAS hearing ‘mocked swimmer’s mother’ Why does this matter? This verdict now means that theoretically Sun is cleared to compete in the pool again. While the 2020 Fina World Swimming Championships have been postponed to December of 2021, the International Olympic Committee is determined that the 2020 Summer Olympics will go ahead in Tokyo in summer 2021. Sun competing for China in Tokyo next year would make international headlines as the court of public opinion has largely turned against him following the initial CAS ruling. Who does this impact? The biggest impact could be on other swimmers who could potentially line up against Sun in Tokyo. The most notable of these is Australian Mack Horton, who famously refused to stand on the podium with Sun after the 400m freestyle at last year’s World Aquatics Championships in Gwangju, South Korea. Horton also refused to shake his hand, which created international headlines. Horton has lost to Sun on a number of occasions in the pool including at the Olympics. The controversy surrounding Sun began in 2014 when the Chinese Swimming Association suspended him for three months after he tested positive for a drug that was banned four months earlier by Wada. The Sun Yang debacle takes another twist What do we know about the verdict? While the Swiss court has not yet released the reasoning behind their judgment in the appeal case, there is speculation that the decision could surround Franco Frattini , Italy’s former foreign minister, who chaired February’s three-member CAS panel that heard the case and then handed the Olympic champion swimmer an eight-year ban. Frattini has posted a number of tweets critical of cruelty to animals in China, describing one person who appeared to mistreat a dog as a “yellow face Chinese monster”. Wada said on Thursday that Switzerland’s highest court had sent the case back to CAS after upholding “a challenge against the chair of the CAS Panel”. What happens next? While the judgment has been thrown out, Wada will get a second chance to pursue the case against Sun. The evidence presented in the case centred on a blood sample that was smashed with a hammer. It is alleged that a security guard, instructed by Sun’s mother, broke the vial casing to ensure it could not be used for testing by Wada. However if the new trial is not completed and a second verdict is not rendered before the Tokyo Olympics, which starts on July 23, 2021, there is a possibility that Sun could represent China at the Games.