Indeed, hijab is an obligation upon all Muslim women during, before, and after Hajj. Each Muslim woman is required by Islam to stick to the Islamic dress code in public and to guard her chastity.
The Islamic Religious Council of Singapore states the following: Hijab is an aspect of chastity and modesty of a Muslim woman. It is a duty that Allah Almighty prescribes for the favor of the Muslim woman, and she has to comply with the command of Allah, thus showing her sincere faith in Allah and fear of His punishment. Allah Almighty says: [And it becometh not a believing man or a believing woman, when Allah and His Messenger have decided an affair (for them), that they should (after that) claim any say in their affair] (Al-Ahzab 33:36).
During Hajj, as in any other condition, it is compulsory for a woman to wear hijab when meeting a non-mahram man and while she is performing her Hajj rituals such as praying, ma
king Tawaf and Sa`i. Apart from that, she is allowed to take off her hijab if she is in her hotel room, etc.