It is said that when a woman performs Hajj, she has to uncover her face. Should she uncover her face while circumambulating around the Ka'bah in this crowd of men
It is not permissible for the woman to wear Niqab (face-veil) while in a state of Ihram (ritual state for Hajj and `Umrah) in the same way she should not uncover her face in the presence of non-Mahram (not spouse or permanently unmarriageable relative) men, whether she is in a state of Ihram or not, but she could let down part of her Khimar (veil covering to the waist) over her face, as
`Aishah (may Allah be pleased with her) said:
Men would pass us when we accompanied the Messenger of Allah (peace be upon him) while we were in the state of Ihram. When they came by us, we would let down the outer garment from the head over the face, and when they had passed on, we would uncover our faces.
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.