HK and Canadian Holidays

yesterday, I found two calendars on my iDevices, I didn't subscribed and can't delete them. On iPad I have HK holidays calendar and on iPhone (same Apple ID), there's Canadian holiday calendar. I think they appeard after the last update. I can't delete them. I'v read few articles on internet that I'm not the only one, who has this problem, however, nowhere read the explanation. Do you know what is it and how can I delete them? Can delete other, but these two...