Ever since the five billionth baby was born on July 11, 1987, it has been observed as World Population Day. The population of the world in 2005 was approximately estimated at 6.396 million. The six billion mark was reached on Oct. 12, 1999. Population, growing at 78 million a year, has doubled since 1960. However, the most noticeable thing is that over 95 per cent of population growth is in developing countries. Whereas, population growth has slowed in Europe, North America and Japan. World population is projected to grow to 9.2 billion by 2050.

Population is growing fastest in the poorest countries. The fastest-growing regions of the world are sub-Saharan Africa, parts of South Asia and West Asia. Their share of the global population has been increasing steadily for the last 40 years.
Within six years, more than half of human beings will live in cities for the first time in history, according to new projections. The world will be increasingly dominated by vast congregation in Asia and Africa. In 1990, the largest cities were London, New York,Paris, Berlin and Chicago. But as per the projections, by 2015,Tokyo, Mumbai, Lagos, Dhaka and Sao Paulo will be the biggest.