If these are residential people who connect directly to their ISPs, there's nothing you can do. This is an issue the ISP would have to resolve if it is indeed a matter of not enough bandwidth to go around because too many people are watching streams and sucking up bandwidth. It's not unheard of that an ISP have slowdowns during peak usage times.
If it's something more local, say like a company or school network, than they should block the websites that are streaming this content and bogging down their networks until the World Cup is over with. That, and fire some lazy employees who should be working and not watching football (soccer).