Sun Yang reacts after winning gold in the 400-meter freestyle at the national summer swimming championships in Hefei, East China's Anhui Province on August 25, 2024. Photo: VCG

After ending his four-year ban in May due to an anti-doping rule violation, China's three-time Olympic champion Sun Yang returned to competition with an emotional victory at the national summer swimming championships.

Representing his hometown Zhejiang Province, Sun won the second-tier race with a time of 3:49.58, after clocking a 3:54.98 in the heat earlier on Sunday. Sun burst into tears twice after finishing each of the races while passing the media zone for an interview.

Fans were thrilled to see Sun's return as the topic "Sun Yang wins 400m free" quickly dominated Chinese social media on Sunday evening. 

Looking at the times of athletes at the national championships held in early 2024, Sun's result in the final made him the fifth fastest in the discipline. 

In June 2021, a panel of the Court of Arbitration for Sport (CAS) announced that Sun committed an anti-doping rule violation "when an unsuccessful attempt was made to collect blood and urine samples from him at his residence on September 4-5, 2018." 

The CAS Panel banned Sun from competition on February 28, 2020 for four years and three months.

Born in December 1991 in Zhejiang's capital Hangzhou, Sun became China's first-ever men's swimming Olympic champion at London 2012, where he won both the 400m and 1,500m freestyle events. Sun remains the Olympic record holder in the men's 400 meters freestyle. 

At Rio 2016 Olympics, Sun won the men's 200m freestyle and  became the first-ever male swimmer to win Olympic gold medals in the 200m, 400m and 1,500m freestyle.

Several elite Chinese swimmers, including Fei Liwei and Zhang Zhanshuo who represented China at the Paris Olympics in men's 400 meters freestyle, skipped the national summer swimming championships for vacations after Olympics. 

According to the national anti-doping management regulations enforced in 2021, Sun is unlikely to be included in future Chinese swimming squads at international competitions as any athletes who have been banned for more than one year due to a doping violation are not eligible to be selected for the national team.

Chen Xinyi, a female swimmer who was able to achieve a top-five performance in national swimming events, has not participated in any international competitions since serving a two-year ban after testing positive for banned substances at the Rio Olympics in 2016.

The national summer swimming championships, running from Sunday to Wednesday, has attracted 499 athletes from 24 teams nationwide.