The official statement from Columbia is at https://president.columbia.edu/content/fulfilling-our-commitments. The link to that was in an email so bland and uninformative that I ignored the links (one of which doesn't work anyway).
My undergrad degree is from Columbia, and I'm a faculty member for a few more months, though no longer teaching. I intend to continue wearing my mask, since I wear it for health reasons and not “for the purpose of concealing one’s identity in the commission of violations of University policies or state, municipal or federal laws.” After all, it's for health reasons, which is explicitly permitted by policy. My next step: an email to my chair and the dean. I have two thesis defenses coming up this semester; other than those, I don't need to be inside any campus buildings, and I'll run the defenses over Zoom if I have to.
https://flipboard.com/@newyorktimes/new-york-bat3un55z/-/a-0zIWJwAfQXmPJsJLILatFg%3Aa%3A3195393-%2F0