Question 94) - When does the difference between severe and light impurity arise?

A: It arises when soiled by them. If someone's body or clothes was soiled with Ghalizhah to the amount of a dirham or less, then the Sarah is allowed but Makruh. If soiled with Khafifah then Salah is allowed as long as the dirt does not reach a quarter of the clothing. If the Ghalizhah is over a dirham or the Khafifah reaches the amount of a quarter of the clothing, then Sarah would not be allowed.

~ al-Quduri ~