Oops, it doesn't look like 'worldwide population day' is a national day..

Other days

healing

Healing Day

pick me

Pick Me Day

book

Book Day

chocolate milkshake

Chocolate Milkshake Day

nail polish

Nail Polish Day

african immigrant and refugee hiv and hep awareness

African Immigrant And Refugee Hiv And Hep Awareness Day

bubble bath

Bubble Bath Day

Emoji Day

boy friend

Boy Friend Day

embarrass your best friend

Embarrass Your Best Friend Day