The Day of Seven Billion, October 31, 2011, is the day that has been officially designated by the United Nations Population Fund (UNFPA) as the approximate day on which the total world population reached a population of seven billion people.
According to the United Nations Department of Economic and Social Affairs Population Division, October 31, 2011 was a symbolic date chosen based on data interpolated from its 5-year-period estimates. The estimates were based on data sources such as censuses, surveys, vital and population registers, and published every other year as part of its World Population Prospects.
The actual date that the world population reached 7 billion has an error margin of around 12 months owing to inaccuracies in demographic statistics, particularly in some developing countries (even the world's best censuses have 1–2% error). Assuming a 1% global error margin, the 7 billion world population had been reached as early as March 20, 2011 or as late as April 12, 2012.
The International Institute for Applied Systems Analysis estimated a date between February 2012 and July 2014.
United Nations Population Fund spokesman Omar Gharzeddine said, "There's no way that the U.N. or anyone could know where or at what minute on the 31st the 7 billionth baby will be born," and the United Nations is not giving official status to this and similar publicity efforts. Nevertheless several newborns were selected by various groups to represent the seven billionth person:
On the Day of Seven Billion, the group Plan International symbolically marked the birth of the 7 billionth human with a ceremony in the Indian state of Uttar Pradesh where a birth certificate was presented to a newly born baby girl, Nargis Kumar, in order to protest sex-selective abortion in the state. The Indian girl to boy ratio for 0–6-year-olds is at 914 girls per 1000 boys nationwide, with Uttar Pradesh's one of the lowest at 889 girls for every thousand boys.