Let's not forget that now the Number of Attendees include non-Catholics who reject Christ, and apostates who reject the moral teachings of the Catholic Church.
Catholic World Report
The official count for the attendance at the final Mass has not yet been released, but the park had an official capacity of 700,000.
Despite the large crowds, the Mass had far fewer people attending than previous World Youth Days. In 2016’s Krakow gathering, the final Mass attendance was estimated at 2.5 million. Even more Catholics showed up for the final Mass on Copacabana beach in Rio de Janeiro – about 3 million.