Independence Day (Academy City)

Academy City's Independence Day is an event that occurs on October 9 of Academy City. It most likely refers to Academy City gaining recognition as an independent city-state despite being an enclave within the territory of Japan.

It is a holiday that is celebrated within the city limits on October 9 of each calendar year.

Battle Royale Arc
On October 9 of the current year of the story timeline, many different organizations from Academy City's darkness take action and attempt to pull off various differing objectives due to the lowered security during the holiday because of security officers taken to increase the war effort.