According to a United Nations report, Delhi is the second most populous city in the world with 25 million population in 2014. Tokyo continues to be the number one with 38 million.
Delhi has almost doubled its population during the last 25 years since 1990. Mumbai is in the fourth position along with Mexico and Sao Paulo all with a population of 21 million in 2014.
According to the UN report the combined population of China, India, US, Brazil, Indonesia, Japan and Russia is more than half of the world population of 7.1 billion.
Today, 11th July, is the the World Population Day. Controlling the increasing population is an important task the world over.