World Population Day is observed on

World Population Day is observed on 11 July, and the date comes from a specific milestone. On 11 July 1987, the world's population was estimated to have reached five billion, which led the United Nations Development Programme to mark the day. The UNDP Governing Council formally established World Population Day in 1989, and the UN has observed it every year since, with themes usually focusing on issues such as family planning, maternal health or gender equality.

• 8 May is World Red Cross and Red Crescent Day, marking the birthday of Henry Dunant, the founder of the movement.
• 5 June is World Environment Day, proposed by the UN General Assembly in 1972 and first observed in 1974 under UNEP.
• 16 October is World Food Day, marking the founding of the FAO in 1945.

For Mains, population issues link to the National Population Policy 2000, the demographic dividend, and the debate on total fertility rate and the sex ratio. Learn the origin of each observance day, not just the date.

Trap: Aspirants mix up the many UN days in June and October. Population is the July day, environment is 5 June and food is 16 October.