China's swimmers head to the Paris Olympics under intense scrutiny as 11 of the squad tested positive for a banned substance before the Tokyo Games. Swimming, a highly anticipated event, sees China competing alongside the United States and Australia for medals. However, revelations in April indicated that 23 Chinese swimmers tested positive for trimetazidine (TMZ) in late 2020 and early 2021 at a domestic competition.

Despite this, they competed in Tokyo after the World Anti-Doping Agency (WADA) accepted Chinese authorities' claims of contaminated food at a team hotel causing the positive results. Eleven of these swimmers, including reigning Olympic and world champions, will compete in Paris, forming a third of China's swim team.

The news, revealed years later through media reports, sparked accusations of a potential cover-up from the United States' anti-doping body, which WADA and China denied. TMZ, a heart medication banned for its performance-enhancing properties, was found in low levels in the swimmers. This drug was also at the center of the Beijing 2022 Winter Olympics doping scandal involving Russian figure skater Kamila Valieva, who received a four-year ban.

The New York Times and German broadcaster ARD reported that three of the 23 swimmers had previously tested positive for another banned substance, clenbuterol, years earlier. Chinese authorities argued that the substance was ingested through contaminated meat, leading to no disciplinary action. WADA stated the clenbuterol levels were significantly lower than its minimum reporting level.

Following the controversy, WADA ordered an independent review of its handling of the 23 cases. Anti-doping expert April Henning criticized WADA's handling, stating the scandal affects not only the agency but also athletes and governing bodies, leaving Chinese swimmers labeled as dopers despite possible contamination issues. Henning emphasized that there are "no winners here."

China has denied any cheating intentions and labeled the allegations as "fake news," with some Chinese media portraying it as an American-led plot to discredit the team.

Among the swimmers alleged to have tested positive is Zhang Yufei, who won two golds in Tokyo and aims to surpass her past performances in Paris. Other medal contenders include Wang Shun, the 200m medley gold medalist in Tokyo, and Qin Haiyang, a multiple world champion and 200m breaststroke record-holder.

China's best-known swimmer, Sun Yang, will not compete in Paris as he recently returned from suspension for his second anti-doping violation.