"Currently, the elderly account for about a quarter of the local registered population, while children under 14 are only 8.6 percent," said Huang Hong, director of the Shanghai Population and Family Planning Commission.
She said that the shortfall in children will work against the city's sustainable development.
By the end of September, Shanghai had a population of 23.7 million, with roughly 14 million registered residents and 9.7 million migrants.
In 2011, about 3.5 million registered residents were aged over 60, and 2.3 million of them were over 65, according to the Shanghai Population and Family Planning Commission.
The number of people aged over 60 will rise by 200,000 a year until 2015, when they will account for one-third of the total registered population.
In recent years, Shanghai authorities have been encouraging eligible couples to have a second child if both spouses are from a one-child family or if the first child has a non-inherited disease.
Even so, few couples want to have a second child.
"Our survey of young couples in the city found that many eligible couples said they wouldn't have another baby for various reasons, such as the high cost of living and career development," Huang said.
According to the population department, in 2011 about 12,000 eligible couples applied to have a second child, but less than half actually did.
This year, only 8.6 percent of Shanghai couples who are both from one-child families have given birth to a second child.
"Financial factors must be considered. The cost of living in big cities like Shanghai is very high. It will not be easy to raise two children in a family, and the quality of life will also be affected," said Huo Xiaohua, 30, mother to an 18-month-old boy.
The city is now experiencing a baby boom, which began in 2006, and is expected to continue until 2017. About 220,000 babies will be born this year, the highest number since 2000 and about 40,000 more than last year.
Despite the growing number of newborns, it still does not match the pace of the aging society.
2012 highway traffic emergency drill held in C China's Hubei