FIFA has announced the code of conduct for World Cup 2026 in United States, Mexico, and Canada, and fans have noticed that vuvuzelas, a horn that became popular during World Cup 2010 in South Africa, have been banned (via Forbes). The from this plastic horns create a tremendous atmosphere, but also potentially dangerous noise levels, which explains why it has been banned from World Cup.
Other competitions also banned vuvuzelas, after even the players complained about the annoying noise from the horns. Vuvuzelas returned in World Cup 2018, mainly used by Iranian fans, and it again triggered a heavy backlash from players and fans.
Other concerns about the presence of vuvuzelas in stadiums include its possibility to be used as a weapon. Besides, a 2010 study found that the tiny droplets emitted from a vuvuzela can make diseases such as flu and cold germs to become airborne for hours.
As a result, FIFA has banned them from the competition, including it in a black list of objects like laser beams and pointers, and plastic water bottles for security reasons.