V S Sunder is my colleague at IMSc. He is a world-renowned mathematician. He travels and lectures widely. He has had multple sclerosis for many years, which means he is confined to a wheelchair (he can walk with a stick and with difficulty for short distances), and therefore suffers various personal inconveniences, but does not inconvenience anyone else (except organizations in India who ignore our accessibility laws, after whom he goes indefatigably!) We hope to have him around for many years longer.
But some others disagree. New Zealand, where his daughter studies, has decided that he doesn’t have an “acceptable standard of health” for a TWO WEEK visa.