Is there any clarification from togashi with his new worktime since 2016? Based on this website there is a continously chapter per years for about 10 chapter for every year that mean 1 tankoubon per years. Since when he decide to work only 10 chapter per years ? Is there any clarification from Togashi or Shueisha ?
The autor is suffering from prolonged back pains and hasn't been able to recover.

While the exact reason isn't always stated, Togashi's chronic illness is a well known issue and mostly assumed to be the reason for pretty much all the hiatuses.