Add Or Delete Holidays And Custom. Is it because they are outliers or zeroes. In the popping Add Holidays to Calendar dialog box please check the specified country whose holidays you want to add.

Now all the existing holidays have been removed from Outlook Calendar. But if you want to remove multiple holidays please hold Ctrl key to select them one by one and then right-click on the holiday among them click Delete to delete all the selected holidays. Click the File Options.
On the top left click Create Custom Term.
Clearly I am. On the top left click Create Custom Term. Scroll through the list of events until you see the Holidays category. In the opened holidays and events list select items you want to delete.