Who chooses them and how?
It's the most representative organ of the Organization, the General Assembly, that designates a particular date as an International Day International days are proposed to the UN General Assembly by Member States. The General Assembly then decides by consensus whether to adopt the resolution establishing the particular day.
The themes of international days are always linked to the main fields of action of the United Nations, namely the maintenance of international peace and security, the promotion of sustainable development, the protection of human rights, and the guarantee of international law and humanitarian action.
In its resolutions, the General Assembly usually explains what prompted it to proclaim the International Day. For example, in declaring 23 May the International Day for the Eradication of Obstetric Fistula, the resolution cited “the interlinkages between poverty, malnutrition, lack of or inadequate or inaccessible health-care services, early childbearing, child marriage, violence against young women and girls and gender discrimination as root causes of obstetric fistula, and that poverty remains the main social risk factor.”
Many people may never have heard about this disease, which causes some of the most devastating injuries that can occur in childbirth, despite the fact that some two million women in developing countries live with it, and between 50,000 and 100,000 new cases occur every year. This is a great example of the crucial awareness-raising job that International Days do.
In addition, this UN body points out in its resolutions which aspects of the problem are of the most concern to UN Member States – or in other words, to humanity as a whole, given that the Assembly is made up of 193 countries, that is, most of the states of the world. A great example of this is the resolution that designates 23 June as International Widows' Day, in which the General Assembly states that it is: "deeply concerned that millions of children of widows face situations of hunger, malnutrition, child labor, difficult access to health care, water and sanitation, loss of schooling, illiteracy and trafficking in persons."
Some of international days are proclaimed not by the General Assembly, but by specialized agencies of the United Nations to draw the attention of the public to topics under their field of expertise, such as health, aviation, intellectual property, etc. For example, World Press Freedom Day, which is celebrated on 3 May, was proclaimed by the United Nations Educational, Scientific and Cultural Organization (UNESCO), based in Paris, and was later adopted by the General Assembly.
In addition to raising awareness, the UN takes advantage of these Days to advise States on actions to tackle the serious problems around which many of these dates revolve. An example is the resolution on the International Day of Biological Diversity, celebrated on 22 May, in which the Organization invites its Member States to sign and ratify the Cartagena Protocol on the protection of biological diversity.
How do we measure the impact of these Days?
The international observances (which also include weeks, years and decades) are some of the most visited pages on the UN website. Each international day has a dedicated website, available in the UN’s six official languages.
The International Days also serve as an indicator of the interest that a given subject attracts in each part of the world. To find this out, we look at the level of engagement that these commemorations receive in different regions and languages across the world. A case well worth highlighting is the International Day of Human Rights, which takes place on 10 December. This Day is observed all around the world with initiatives ranging from military and police officers swapping guns for running shoes in South Sudan, to a student competition in Russia, or a exhibit in Brazil. All in all, a multitude of individuals from all walks of life get involved, in a way or another, in the celebration of this special day.
You may also be interested to know that 21 March is the date of five different international days, and June is the month with the most international days.