September 8 - International Literacy Day

September 8 was proclaimed International Literacy Day by UNESCO on November 17, 1965. It was first celebrated in 1966. Its aim is to highlight the importance of literacy to individuals, communities and societies. On International Literacy Day each year, UNESCO reminds the international community of the status of literacy and adult learning globally. Celebrations take place around the world.
Links
1.United nations page
2.Literacy

August 26 - Namibia Day

Heroes' Day (also known as Namibia Day) is a national public holiday in Namibia. It is recognized by the United Nations as Namibia Day. Celebrated annually on 26 August, the day commemorates numerous events in Namibian history. Officially, the day commemorates those Namibians who died for independence, especially during the Namibian War of Independence which began on 26 August. Since Samuel Maherero's return from exile for burial in 1923, The Herero people have commemorated 26 August as a gesture of defiance.

August 12 - International Youth Day

International Youth Day (IYD) is an awareness day designated by the United Nations. The first IYD was on 12 August 2000. As with other political awareness days, such as Earth Day, the purpose of the day is to draw attention to a given set of cultural and legal issues surrounding an endangered demographic. International Youth day is on August 12 each year. It was designated by the United Nations in 1999 by the adoption of resolution 54/120
Links
1.UN Youth day

August 9 - International Day of the World's Indigenous People

The term indigenous peoples can be used to describe any ethnic group of people who inhabit a geographic region with which they have the earliest known historical connection, alongside immigrants which have populated the region and which are greater in number.
On 23 December 1994, the General Assembly decided that the International Day of the World’s Indigenous People shall be observed on 9 August every year during the International Decade of the World’s Indigenous People (resolution 49/214).
Links:
1.UN Page

July 11 - World Population Day

World Population Day is an annual event, observed on July 11, which seeks to raise awareness of global population issues. The event was established by the Governing Council of the United Nations Development Programme in 1989. It was inspired by the public interest in Five Billion Day on July 11, 1987, approximately the date on which the world's population reached five billion people.

The world population on the 20th anniversary of Five Billion Day, July 11, 2007, was estimated to have been 6,727,551,263.
LInks:
1.United Nations population fund
2.World Population Day

June 26 - International Day against Drug Abuse and Illicit Trafficking

The International Day against Drug Abuse and Illicit Trafficking is a United Nations International Day against drug abuse and the illegal drug trade. It has been held annually since 1988 on 26 June, a date chosen to commemorate Lin Zexu's dismantling of the opium trade in Humen, Guangdong, just before the Opium War .The observance was instituted by General Assembly resolution 42/112 of 7 December 1987.
Links:
1.Wikipedia
2.UN Page

June 23 - United Nations Public Service Day

The UN General Assembly, in its Resolution 57/277, designated 23 June as Public Service Day (A/RES/57/277). The UN Public Service Day intends to celebrate the value and virtue of public service to the community; highlight the contribution of public service in the development process; recognize the work of public servants, and encourage young people to pursue careers in the public sector. Within the Public Service Day, the UN have established annual Public Service Awards for the positive achievements in the public service.

The United Nations Public Service Awards is the most prestigious international recognition of excellence in public service. It rewards the creative achievements and contributions of public service institutions that lead to a more effective and responsive public administration in countries worldwide.