How do I cover my face in iḥrām since the niqab is prohibited?
What is prohibited is the garment, not the covering. A woman in iḥrām may let a cloth down over her face — isdāl. The schools differ only on whether it must be held clear of the skin.
This is the clearest case of a distinction that runs through the whole subject: the niqab is a garment; covering the face is an act. Confusing them produces the wrong answer here.
What is actually prohibited
The niqab, the burquʿ, and any garment made specifically to cover the face.
The prohibition is on wearing those things. It does not mean a woman in iḥrām must leave her face exposed.
Isdāl
The permitted method is isdāl: letting the cloth already worn on the head fall forward over the face.
This is what the reports of the earliest Muslim women in iḥrām describe — they covered their faces, but not with a niqab.
Where the schools differ
Ḥanafī and Shāfiʿī require the cloth to be held away from the skin of the face, understanding the prohibition to extend to anything touching it. Unavoidable brief contact is excused.
Mālikī and Ḥanbalī impose no such condition. On their view what is prohibited is a purpose-made face covering, not ordinary cloth resting against the face — provided it is not fastened, stuck, or tied on in the manner of a niqab.
The Mālikī–Ḥanbalī position is preferred, described as more accurate. That is a stated preference, not a settled ruling.
In practice
Two practical aids address different problems.
A thin cloth, because isdāl covers the eyes as well and so obstructs sight and movement. This is noted as the practice of some Arab women on ḥajj and ʿumrah, and suggests it may be what Imam Aḥmad meant by "she lets down something thin over her face."
A cap with cloth hung in front of it, worn by pilgrims today. This one does address the Ḥanafī and Shāfiʿī condition: it holds the fabric clear of the face without occupying the hands.
Check your understanding
What exactly is prohibited for a woman in ihram, according to the note?