What is the ruling on carrying a mus'haf (copy of the Qur'an) in a school bag and reciting from it in public places and on means of transport that contain reprehensible things which are difficult to remove?

It is permissible for a Muslim to carry the complete Mushaf (copy of the Qur'an) or a part of it in their wallet if the intention is to carry the wallet, even if they are not in a state of complete ritual purity (taharah).

However, if the intention is to carry the Mushaf and it is placed in the wallet, it is not permissible except in a state of complete ritual purity according to the Malikis, except for the teacher and the student, who are permitted to touch the Mushaf without wudu'.

The Hanbalis permit carrying the Mushaf by a strap, cover, or sleeve for one who is not ritually pure, and this opinion is closer to what is correct.

As for reciting the Qur'an, it is recommended at all times, with the exception of public places where voices are raised and objectionable acts are present.