The Grand Ayatollah Safi answered questions about taking upper body clothes off in mourning ceremonies.
Question: Is it allowed to beat the chest whilst taking upper body clothes off in mourning ceremonies of Imam Hussain (AS)?
The Grand Ayatollah Safi: There is no problem if it is certain that non-Mahrams are not looking.
Question: What is the ruling if taking off upper body clothes in mourning ceremonies is provocative?
The Grand Ayatollah Safi: There is a problem if it is provocative, and it is better to participate in mourning with clothes on.
source : shafaqna
