Random question:
Are riders allowed to take off jackets while riding, or do they have to in pit to do so?
Is it even possible to take off your jacket while riding? Unlike in road cycling, there aren't a lot of long stretches where you are just pedaling, and even there taking off a jacket can be... complicated... as Kelderman showed us a few years ago.
I'd have to go read the UCI rule book to know for sure (
not going to happen now) but I think that you can remove/add as needed/able anywhere on the course. Do they have litter zones in CX like on the road now though?
EDIT:
5.1.063 The riders undertake to respect nature and the environment throughout the course and not to pollute the site. The littering zone will be the pit area along its entire length. Waste must be deposited on the side of the course. It is strictly forbidden to throw waste directly onto the course or outside the designated area.(article introduced on 01.07.25)
5.1.038 A rider may only take the pit lane to change his bicycle, wheel(s) or for other mechanical assistance. Should a rider take the pit lane for any other reason, the commissaires shall decide and the decision shall be final.
The only thing that I could find specifically about clothing discusses what they must wear (UCI approved team or national kits).
Rules & Official documents of the UCI
www.uci.org