I do not know. But... whatever is happening there, it must be big, to cause disruption on this scale.

Although, if I were to hazard a guess... Daiki-san said something about a group seeking to take over all worlds, which means they were going to physically come to every world... which suggests they had to connect their world to our worlds, somehow, and that was how we came under attack. It also created the tower we all saw. Perhaps this is something that should be taken into consideration?