Is removing the niqab among the major sins or the minor ones? Thank you.

Scholars have differed regarding the ruling on a woman covering her face in front of non-mahram men. The preponderant opinion is that it is obligatory, but uncovering the face is not among the major sins; rather, it is among the minor ones. Nevertheless, one must not be lenient with minor sins, for they can destroy their perpetrator if they accumulate. It has been said: "There is no small sin when accompanied by persistence."