All four schools of Islamic jurisprudence agree that men in the state of ihram are prohibited from wearing clothing that is sewn or stitched to fit the body's contours, such as shirts, trousers, turbans, socks, and shoes that cover the ankles. The man in ihram should wear two unstitched white sheets: the izar (lower garment wrapped around the waist) and the rida (upper garment draped over the shoulders). This is based on the explicit instruction of the Prophet Muhammad (peace be upon him) regarding what a muhrim should not wear.
If a man wears stitched clothing intentionally and without a valid excuse, he is required to pay a fidyah as expiation. The fidyah, as detailed in the Quran (2:196) and the hadith of Ka'b ibn Ujrah, gives the pilgrim three options: fasting for three days, feeding six poor people (each receiving half a sa' of food, approximately 1.5 kg), or slaughtering a sheep. If the violation was due to forgetfulness or ignorance, scholars differ — the Hanafi school still requires fidyah, while other schools may show leniency depending on the circumstances.
It is important to note that this prohibition applies only to men. Women in ihram may wear their regular modest clothing, including stitched garments. However, women are prohibited from wearing the niqab (face veil) and gloves during ihram, though they may cover their faces with a loose cloth when non-mahram men are present. The wisdom behind these restrictions is to cultivate humility, equality, and detachment from worldly adornments during the sacred pilgrimage.