Flag Day:

A flag day is a flag-related holiday—either a day designated for flying a certain flag (such as a national flag), or a day set aside to celebrate a historical event such as a nation's adoption of its flag.
Flag days are usually codified in national statutes, however, in some countries a decree by the head of state can also order a flag day. The statute or decree may specify locations where flags are flown and how are they flown (for example, at full- or half-staff); alternatively, custom may prevail.
In the United States, Flag Day is celebrated on June 14. It commemorates the adoption of the flag of the United States, which happened that day by resolution of the Second Continental Congress in 1777. The largest Flag Day parade is held annually in Troy, New York, which bases its parade on the Quincy parade and typically draws 50,000 spectators.

The Armed Forces Flag Day or the Flag Day of India is a special day dedicated towards collection of funds from people of India, for the welfare of the armed forces personnel in India. It is observed on December 7, every year in India, from 1949. Funds are collected from the general public for the welfare of the Indian Armed Forces personnel. Over the years, it has become a tradition to commemorate this day as an honor to the brave soldiers, airmen and sailors of India.