In this file photo taken on July 21, 2019 Silver medalist Australia's Mack Horton (L) refuses to stand on the podium with gold medalist China's Sun Yang (C) and bronze medalist Italy's Gabriele Detti after the final of the men's 400m freestyle event during the swimming competition at the 2019 World Championships at Nambu University Municipal Aquatics Center in Gwangju, South Korea, in this July 21, 2019 file photo. — AFP