If a person wants to perform ‘Umrah while he is ill and cannot wear the clothes of ihram (ritual consecration), is it permissible for him to wear ordinary clothes, such as a shirt and pants?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

If a person is able to perform ‘Umrah, yet he cannot wear a rida’ and izar (upper and lower garments worn in ihram) and has to wear form-fitting clothes due to an illness or a similar reason, then there is nothing wrong with that and he incurs no sin given that he has an excuse. What is required of him in such a case is to offer an expiation, choosing any of three proposed options, just like the expiation mentioned in the verse (which means): {…And whoever among you is ill or has an ailment of the head [making shaving necessary must offer] a ransom of fasting or charity or sacrifice…} [Quran 2:196] The fasting mentioned in the verse is for three days, charity is to feed six poor persons and sacrifice is to slaughter a sheep, as mentioned by the Prophet, sallallaahu ‘alayhi wa sallam, in the Hadeeth of Ka‘b ibn ‘Ujrah.

Allaah knows best.