20 May 1981
An International Conference on Sanctions against South Africa was hosted by the United Nations (UN) and the Organisation of African Unity (OAU) at UNESCO House in Paris, France. The UN had been vocal about the apartheid policy since the early 1950s. On 1 April 1960, the UN Security Council, in its first action on South Africa, adopted Resolution 134 condemning the policies and actions of the South African government in the wake of the Sharpeville massacre, where nearly 70 peaceful protesters were killed by the police on 21 March. The Security Council called upon the government to abandon its policies of apartheid and racial discrimination.
References

United Nations, ‘The United Nations: Partner in the Struggle against Apartheid’, [online], Available at https://www.un.org [Accessed: 19 April 2013]|O’Malley, P., (1981), 'Declared the Year of the Youth to pay tribute to the heroism displayed by the youth'. from Nelson Mandela Centre of Memory, [online], Available at www.nelsonmandela.org.za [Accessed: 19 April 2013]