NEW YORK—As world authorities gathered in Manhattan to participate in the 76th session of the United Nations (U.N.) General Assembly at its headquarters this week, a group of Falun Gong practitioners quietly meditated and held banners raising awareness about their persecution by the Chinese Communist Party (CCP). Falun Gong, also known as Falun Dafa, is a spiritual practice that includes meditation exercises and teachings based on the principles of truthfulness, compassion, and tolerance. It grew in popularity during the 1990s, and 70 million to 100 million people were practicing in China by the end of the decade, according to official estimates at the time. The CCP felt threatened by its popularity and launched a systematic elimination campaign in July 1999. Since then, millions of practitioners have been detained inside prisons, labor camps, and other facilities, with hundreds of thousands tortured while incarcerated, according to the Falun Dafa Information Center. Jacek …