China's one child policy may succeed in keeping its population pegged below 1.5 billion mark by 2050 but the country may end up with over 350 million pensioners as one out of every four people will be over 65 years by that time.
The population will peak around the year 2040 at about 1.47 billion before starting to decline, he said, citing a forecast from the centre's population administration decision information system.
China's population will also make up 15 per cent of the world's population, down from the long time 20 per cent and above, Jiang was quote by China Daily today as saying.
The country's family planning policies have helped prevent 400 million births in the past three decades, according to statistics.
China's current fertility rate is 1.8, which means every woman giving birth to 1.8 children.
That rate is ideal, said Hania Zlotnik, director of the population division of the United Nations Secretariat said.
A fertility rate lower than 1.5 or higher than 2.3 will be problematic, she said. However, the ageing trend is irreversible in China, as by 2050, 350 million out of the total 1.45 billion Chinese people will be aged over 65, Jiang said.
China has already got about 180 million people above 60 years by last year, according to earlier population reports.
China will see two peaks in its ageing population - a net growth of 7 million annually between 2015-2020 and 10 million annually between 2030-2035.
"More families of old couples living by themselves, or a single elderly person living alone, will appear by then. The changes in family size, structure and living arrangement will impact many things, including consumption structure and the elder-age security system," Jiang said.
Ageing can lead to labour shortage, lower productivity and skyrocketing medical expenses, Wu Cangping, a professor with Renmin University of China said. However Jiang believes that China will not be short of workers.
The labour supply will peak at one billion around 2015 and remain above 850 million before 2050.
Ma Li, a counsellor to China's Cabinet on population issues, said that the country can still enjoy 25 more years of "demographic dividend".
China at present continues to pursue one child policy vigorously despite apprehensions over future labour shortages and steady increase in ageing.
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