By Francis Markus BBC News, Shanghai

Tempering the sadness, though, is the fact that the deceased woman was over 100. Among those mourning her was one of her daughters - aged 80.

Soon there may not be enough carers for the elderly

This family's longevity may be quite exceptional. But the fact that people are living longer is a key factor in China's changing population structure.

Another, as one village primary school I visited shows, is declining birth rates.

The buildings are too big for the number of children. The class which they are joyfully trooping out of is two separate age groups bunched up together.

The country's strict birth control policy is obviously a key factor, even if it's applied less rigidly in the countryside than the cities.

And it is having a noticeable effect on the economy.

"Nowadays many rural families don't want to send their children to work in the factories because they have only have one child and they regard that child as their insurance policy for old age," said Feng Shengping, senior researcher at a Communist Party think tank in southern China.

"But we ought to regard a child not as our insurance policy but as someone making a contribution to the whole of society. And at the same time channel the insurance function into a social welfare system."

In 15 or 20 years' time we are likely to have a much older population with a much higher percentage of people in retirement and a lower percentage of people supporting them Arthur Kroeber, China Economic Quarterly

At the TF Sunny clothing company in Shanghai, the managing director, Ma Weimin, is already thinking ahead to a time when being in a labour- intensive industry could start to become a liability.

"Our main effort will continue to go on the garment industry, but meanwhile I will also look for other areas to do other business besides the garment business which don't involve so many people doing it."

Some Chinese scholars have warned that in 15 or 20 years' time, China will face an ageing population problem similar to that encountered by several developed countries, but without the welfare resources to meet the challenge.

One-child policy

But Arthur Kroeber, managing editor of the China Economic Quarterly, isn't so sure.

"Demographic projections are very perilous because we don't know what tomorrow's birth rate is going to be," he said.

"But basically it does seem clear right now that China is in the midst of a demographic boom where there's a bulge of young people and that bulge is going to get older and older, and in 15 or 20 years' time we are likely to have a much older population with a much higher percentage of people in retirement and a lower percentage of people supporting them."

Demographers have started warning that the country might need to relax its birth control policy to allow two children per family even in those areas where a one-child limit has been strictly enforced.

But in Shanghai, although the authorities are trying such measures, for economic and social reasons few couples are so far opting to have a second child.