Editor's note: As athletes around the world compete in the 2024 Paris Olympics, a fierce row over anti-doping issues is intensifying among global anti-doping communities. CGTN rolls out a series of reports to show the U.S.'s role in the controversy and how its dominance in international sports is harming global anti-doping rules.

As Chinese athletes amaze the world again with their record-shattering performances at the ongoing Paris Olympic Games, some athletes and media outlets have cast doubts about how they got there.

In April, a New York Times story claimed that 23 top Chinese swimmers had tested positive for the banned drug trimetazidine, known as TMZ, but escaped punishment as some went on to compete in the subsequent Tokyo Olympics in 2021.

Meanwhile, the U.S. Anti-Doping Agency (USADA) accused the World Anti-Doping Agency (WADA) of "inaction" and a "cover-up" in accepting China's findings that suggested their swimmers unknowingly ingested the substance from food eaten at a hotel.

In response, WADA invited an independent prosecutor to investigate its handling of the case which found no evidence of favoritism by the organization.

Despite the finding, U.S. officials have threatened to sanction the agency by imposing new laws that would give relevant authorities the power to withhold membership fees worth over $3 million.

The law is "a tool for USADA to put itself above the rest of the world, perhaps even to replace WADA as the global regulator for anti-doping," said WADA President Witold Banka at a session of the International Olympic Committee (IOC) in Paris on July 24, two days before the opening of the 2024 Olympic Games.

"This cannot be allowed to stand," said Banka. He warned that if U.S. authorities assert jurisdiction over cases that have nothing to do with them, it risks putting the U.S. outside the global anti-doping system.

Records show that Chinese athletes competing in the Olympics go through more frequent testing compared to athletes from other countries. While each Chinese swimmer is tested 21 times on average in the lead up to the Paris Games, the number is six for the Americans, five for the Italians and four for Australians according to data from World Aquatics, a governing body recognized by the International Olympic Committee.  

Most importantly, they also compete clean with 0.2 percent of doping violations detected in 2022, which is significantly lower than the U.S. and Canada, according to data by WADA.

Prejudice and injustice against Chinese athletes at international sporting events have infuriated many, including Chinese swimmer Zhang Yufei who questioned why athletes such as Phelps have not faced the same scrutiny when he shattered records and won eight gold medals in a single Olympic event.

Zhang, who participated in this year's Paris Olympics, pointed out that Chinese athletes already go through a rigorous if not tedious testing process for banned substances by official agencies such as WADA.

"I don't think the incident will have a serious impact on us," she said. "Because we are innocent. The World Aquatics and all relevant parties have sorted it out very clearly and made clarifications on the internet. If that's not enough to clear the doubts of some people, then there's no point in making further meaningless rebuttals (to make them believe)."

Many have come to the defense of Chinese athletes on the internet. "It's just pure racism!" read one comment that gained nearly 3000 likes. "The belief is that U.S. and Australian swimmers are faster than Chinese swimmers – so if the Chinese win – they must be cheating – because Chinese swimmers cant swim as fast as they can! It's just plain old racism!"