Hong Kong, China - In shadows cast by streetlights in the pre-dawn hours, a diminutive figure shuffles along, hunched over a cart.

She stoops to pick up a discarded piece of cardboard. Other people's rubbish is much-needed income for her.

This is how Fok Po Po starts the day, seven days a week, in Hong Kong's stifling humidity, torrential rain and epic thunderstorms.

Fok Po Po - or "grandma" in Cantonese - is 66. She's worked hard all her life and invested in a retirement fund.

But in Hong Kong, one of the world's most expensive cities, Fok Po Po is one of a growing number of elderly people resorting to collecting rubbish to survive.

In this city of seven million people, where more Rolls-Royces roam the roads than anywhere else on earth, about one third of residents aged over 65 live in poverty.

They are the face of Hong Kong's "silver tsunami" - as people live longer and the workforce shrinks, the ranks of the elderly poor are growing, putting more pressure on the government and families to care for them.

"Many old folks face this money problem where welfare doesn't keep up with rising living costs …. It's considered normal," Fok tells Al Jazeera.

In one of the world's leading finance hubs, elderly residents can apply for several different types of government benefits.

But community advocates say the existing benefits are not enough to cover living expenses, and that it's difficult for people with children to obtain welfare.

Workers and their employers must contribute to a compulsory retirement fund but this system began only 16 years ago.

Ng Wai Tung, a community organiser from the Society for Community Organisation, a non-profit group, says this means many elderly residents do not have enough savings to support themselves in their old age.

He cites the case of a woman who worked as a cleaner. When she turned 65, she had only about $6,400 in her retirement fund.

"This amount meant she could not afford to live in Hong Kong for more than one year, due to the expensive rent .... Now she needs to pick up cardboard and work as an illegal hawker at night," he says.

'Respect the elderly is only a slogan'

Hong Kong has some of the world's most expensive rental properties, and older people often struggle to find a home they can afford.

Many rent tiny rooms in small apartments that have been sub-divided in order to cram in more residents. Some places are so small and claustrophobic that they are nicknamed "coffin homes".

The Society for Community Organisation believes introducing a universal pension would help to ensure that the elderly have a better standard of living.

While Chinese culture has a long tradition of taking care of the elderly, Ng says low-income earners often cannot afford to support their parents. He believes it is the government's responsibility to provide for them.

But not everyone agrees.

Dominic Lee is a young politician from the right-wing Liberal Party who opposes a universal pension.

"Resources should not be just a handout, should not be an entitlement," he says. "People have to be accountable for themselves and for their own family."

Educated in the US, Lee is the son of entrepreneurs who built their family company from scratch.

He says Hong Kong's low tax rates help attract vital foreign investment. Raising taxes to provide more elderly people with welfare benefits would drive big businesses away, he argues.

"I think this level of tax is going to discourage a lot of corporations from coming to Hong Kong," he says. "We are facing tremendous competition from other countries such as Shanghai and Singapore and we are losing this battle when corporations look at where they place their business."

Many of Lee's constituents are elderly and his office is close to the poor neighbourhood of Sham Shui Po, where residents such as Fok Po Po collect rubbish to make ends meet.

"On a personal level, I sympathise with them a lot because the government needs to do a lot of things to help them," he says. "But on a policy level … we shouldn't let things on an emotional level affect our decision because resources that we use to help one person could be used to help other people."

On a recent afternoon in Sham Shui Po, people hurried past electronics stores selling the latest mobile phones, seemingly oblivious to the old man scavenging through a garbage can.

Ng says the poor are often ignored in Hong Kong because the education system emphasises the need to be self-sufficient.

"Usually 'Respect the Elderly' is only a slogan. It doesn't have any real or deep meaning in this society," he says.

Too poor to get by

Fok Po Po, who served in the Chinese army and came to Hong Kong from the mainland in 1999, says she never wanted to have to rely on the government.

But her retirement savings lasted only a year.

The monthly rent for her small sub-divided flat, which she shares with her two sons and granddaughter, costs $540 but she gets only $300 in government welfare.

"I have to support them because they don't earn enough to stay on their own," she says of her children.

Collecting cardboard helps pay for food and the medication she needs to treat a back injury she suffered while working as a government street sweeper.

But with the ranks of the elderly growing, competition for cardboard to sell is tough.

"Often we really have to fight for it and you have to guard your territory and the area where you want to collect," she says. "There's lots of competition and a lot of old ladies like me who work until the middle of the night because we don't have enough funds to live."

They may toil beneath glittering lights in a city awash in designer handbags and luxury brands, but for many residents, growing old in Hong Kong is a lonely and desperate battle.

From the 101 East documentary, Hong Kong: Aged and Abandoned. Watch the full film here.

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Follow Liz Gooch on Twitter: @liz_gooch