ANSWER: National Maths Day
India on 22nd December 2015 celebrated the birth anniversary of well known Indian mathematician Srinivasa Ramanujan as the National Mathematics Day. India and UNESCO agreed to jointly spread the knowledge and joy of learning the subject to Indian students on this day. A conference on the Zero was held in UNESCO HQ in Paris and IISc Bengaluru in recognition of the invention of zero by Indian mathematician Aryabhata. The declaration to observe 22 December as National Mathematics Day was made by ex Prime Minister Dr. Manmohan Singh on 26 February which was the 125th birth anniversary of Ramanujan.