In a bid to help break taboos around toilets and make sanitation for all a global development priority, the United Nations General Assembly designated 19 November as World Toilet Day. World Toilet Day has previously been marked by international and civil society organizations all over the world. However, it was not formally recognized as an official UN day until 2013.
2017 theme: Wastewater
World Toilet Day 2017 continues the theme from World Water Day earlier this year, with the focus on wastewater.
Source- United Nations