Oops, it doesn't look like 'flags are sold in market on large scale on the occasion of independence day' is a national day..

Other days

Self Appreciation Day

Cursing Day

Bow Tie Day

Tell A Fairytale Day

Tell Ur Crush You Like Them Day

My Little Pony Day

Emoji Day

African Immigrant And Refugee Hiv And Hep Awareness Day

Artists Day

Hannah Day