World Fish Migration Day
World Fish Migration Day is held on April 21. This event in the third decade of the month april is annual.
UN Chinese Language Day on April 20 (United Nations);
International Girls in ICT Day on April 22 (aims to encourage and empower girls and young women to consider studies and careers in the growing field of Information and communications technology);
Chemists Celebrate Earth Day in USA on April 22 (In 2003, the American Chemical Society joined in on April 22's festivities. Each year, ACS highlights one of four general topics and chooses a themeóthis year it's "Our Earth: Handle With Care"óto focus the celebration and highlight how chemists can contribute to a greener world);
International Pixel-Stained Technopeasant Day on April 23 (The Day is declared by author Jo Walton, held on April 23 and first celebrated in 2007, in response to remarks made by Howard V. Hendrix stating that he was opposed "to the increasing presence in our organization the Science Fiction and Fantasy Writers of America of webscabs, who post their creations on the net for free". The purpose of the day, according to Walton was to encourage writers to post "professional quality" works for free on the internet. The name of the day originates from the assertion by Hendrix that the "webscabs" are "converting the noble calling of Writer into the life of Pixel-stained Technopeasant Wretch.");
UN English Language Day on April 23 (United Nations);
UN Spanish Language Day on April 23 (United Nations);