More than 20 countries - including Japan, Spain, Italy, Thailand, Portugal, South Korea and Poland - will see their numbers diminish by at least half.
Nigeria's population is expected to leap from 190 million today to 410 million by 2050 and to almost twice that number again by the end of the century.
China's government raised the limit to two children in 2016 to rejuvenate the world's most populous country, which has nearly 1.4 billion people, and experts say it may remove the cap next year.
Leonel Maia of East Timor has been there nearly seven years. Filipina Gladys Gayeta is a newly arrived trainee factory worker, but must leave in less than three years.
But data from a variety of sources – including the UN and the World Bank – indicates that the total number of live births is falling around the world, including in developing nations.
South Africa has been battling drought with the Western cape seeing the worst of it since 1904.
The adoption of green building technologies and solutions is a key part of China’s sustainability and environmental protection goals.
While some nation states are exhibiting neo-imperial tendencies, most are waning in power and influence.
Greater Cairo, a metropolitan area including Cairo and parts of the Giza and Qalyubia provinces, is home to some 22.8 million people.
One in five children in sub-Saharan Africa, or 148 million, will be living on less than $1.90 a day in 2030.
The data was collected from 1.3 million households across all South African communities.
Gwinyai Masukume and Victor Grech explain what factors result in more male than female children being born.
How many people are there in the world?
UN predicts Nigeria may replace the US as the country with the third largest population.
South Africa now has a total population of nearly 55 million people.
PM Narendra Modi promised 100 so-called smart cities by 2022 at a cost of $1 trillion.
