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

Camera Day

Offer Day

Eat What You Want Day

Frozen Yogurt Day

Kiss A Brunette Day

Unicorn Day

Get Funky Day

African Immigrant And Refugee Hiv And Hep Awareness Day

Ponytail Day

Girl Friend Day