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

Other days

boba

Boba Day
hiv awareness

Hiv Awareness Day
gallery

Gallery Day
bow tie

Bow Tie Day
get funky

Get Funky Day
my little pony

My Little Pony Day
african immigrant and refugee hiv and hep awareness

African Immigrant And Refugee Hiv And Hep Awareness Day
self appreciation

Self Appreciation Day
aloxolt

Aloxolt Day
boyfriend

Boyfriend Day