International Day of Older Persons: 1 October

The International Day of Older Persons is observed on October 1 each year to recognize the contributions of older persons and to examine issues that affect their lives. The theme for the 2018 celebration is “Celebrating Older Human Rights champions”.
On December 14, 1990, the United Nations General Assembly voted to establish October 1 as the International Day of Older Persons.  The day was observed for the first time on October 1, 1991. The day is celebrated by raising awareness about issues affecting the elderly, such as senescence and elder abuse. 
Source- The United Nations