The date for WDSD being the 21st day of the 3rd month, was selected to signify the uniqueness of the triplication (trisomy) of the 21st chromosome which causes Down syndrome.
WDSD was first observed in 2006 in many countries around the world and Down Syndrome Association Singapore launched and hosted the WDSD website from 2006-2010, on behalf of DSi, for global activities to be recorded.

On 19 December 2011, the United Nations General Assembly declared 21 March as World Down Syndrome Day. The General Assembly decided to “”designate 21 March as World Down Syndrome Day, to be observed every year beginning in 2012″” and “”invites all Member States, relevant organizations of the United Nations system and other international organizations, as well as civil society, including non-governmental organizations and the private sector, to observe World Down Syndrome Day in an appropriate manner, in order to raise public awareness of Down syndrome””.

In this video Dr Mukesh Gupta , an Eminent Obstetrician
& Gynecologist from Le”Nest, Malad , Mumbai explains about this genetically caused condition which may cause lifelong Physical/ Cognitive/Emotional issues in the Child.