"Religious holidays" refers to specific days that hold significance and are observed by followers of a particular religion. These days are usually seen as important and are set apart for religious observance, practices, or celebrations.
I have no problem with this except that schools do not close for religious holidays. (religion.blogs.cnn.com)
Other families celebrate birthdays, mother's day and father's day, while others celebrate religious holidays and ceremonies. (sanfranciscomarriagecenter.com)
We also hold special services here on religious holidays. (floatinghospital.org)