When did the 2nd edition of the International Day of Light is celebrated?

May 16 is celebrated as International Day of Light. This the 2nd edition of the International Day of Light. UNESCO (The United Nations Educational, Scientific and Cultural Organization) officially observes the International Day of Light so as to continuously appreciate light and for the exemplary role it plays in science, culture and art, education, sustainable development, medicine, communications, and energy. special focus of celebrations on this day is the 'Illuminating Education conference' that was held at the UNESCO Category 1 Institute ICTP in Trieste where presentations have covered a wide range of topics, namely, science education, challenges on diversity and gender equality, and practical career advice. The overall program was titled "Illuminating Education".