(Image source from: Delhi becomes world's second most populated city})

Delhi has achieved a another distinction by becoming the world's second most populated city in 2014. And Tokyo is the most populous country in the world.

Since 1990, Delhi's population has more than doubled to 25 million, a UN report suggested.

India is expected to add the most number of people to its urban centres, even more than China, by 2050, according to the 2014 revision of the World Urbanisation Prospects launched on Thursday.

However, Delhi is likely to retain its position of the second most populous city in world till 2030 at least. By then Delhi's population is expected to increase to 36 million.

Tokyo was at the top spot in UN's ranking for most populous cities in 2014. At present it has 38 million people, which is expected to decline. Tokyo will continue at the top spot till 2030, when its population is projected to be 37 million.

Mumbai ranks sixth among the most populous cities in the world for 2014. But it's expected to reach the fourth spot in 2030, with a projected population of 28 million. Mumbai's current population is 21 million.

Shanghai is world's third most populous city with 23 million, while Mexico City, Mumbai and Sao Paulo each have around 21 million population in 2014 report by UN.

According to this report, the largest growth in urban population will take place in India, China and Nigeria during 2014 to 2050. These three countries will account for almost 37 & of the projected growth in urban population.

By 2050, India is expected to add 404 million urban dwellings, much more than China's projected figure of 292 million. While, Nigeria is expected to add 212 million.

Currently, India's urban population is 410 million, which is projected to grow to 814 million by 2050. While China currently 758 million, which is world's largest urban population.

Together, India and China, add up to 30 % of urban population in the world.

India, China, United States, Brazil, Indonesia, Japan and Russia together constitute over 50 % of the world's urban population.

Currently, the world's urban population is almost 3.9 billion. It's projected to touch 6.3 billion by 2050.

Almost 3.4 billion people around the world reside in rural areas at present. By 2050, the world's rural population is projected to decline, which will reach 3.2 billion.

At present India has the world's largest rural population with 857 million, while China has 635 million people living in rural areas.

(AW: Pratima Tigga)