Viewers of the New England Patriots vs. Oakland Raiders game on CBS on Sunday didn't hear the gay slurs being chanted by people in the stands in Mexico City, because the network added crowd noise.

According to a report from OutSports, Mexico soccer fans chant gay slurs when opponents have free kicks. In Sunday's game, the Raiders were the home team, so when the Patriots kicked, fans yelled the slurs.

CBS went into the game expecting it because it's not new. When the Raiders played the Houston Texans in Mexico City last year, the slur “puto,” which translates as "male prostitute," was heard clearly during ESPN’s telecast.

Mexican soccer officials have asked fans not to use it, but it continues to be an issue during international soccer matches. FIFA has fined the team because of it.

First popularized in Mexican stadiums, the chant was heard on the global stage in 2014 in Brazil during the World Cup and then spread to fans of some other countries in the Americas.