One-third of the total homeless population in the US are people with untreated serious mental illnesses

Human feces and urine litter sidewalks. Used syringes and the bodies that sucked in their fluid stretch out among it.

Hoteliers worry about tourists being scared away. Politicians pledge to provide more housing, while activists blame a lack of will from the leaders.

And the homeless problem that has exasperated San Francisco's city leaders for decades despite millions of dollars spent on it has gotten worse, say those who live and work among it and those struggling to deal with it.

An estimated 7,500 people live on the city's streets and in its parks, with many of them categorized as chronically homeless, defined as homeless for more than a year, according to the city's count conducted by volunteers on a night in January 2017.

A quarter of the homeless live on the streets because of unemployment, while other causes include alcohol and drug abuse, divorce and losing housing, according to the San Francisco 2017 Homeless Count and Survey report.

Winona, 71, said she has been homeless since she lost her job a few years ago. "I'm trying to figure out what job I can do," she said, giving only her first name. "Sometimes they (the government's aid programs) work, sometimes they don't."

In jeans and a denim jacket, and wearing a pink sun hat, Winona stood on a business street, asking for help from passersby in a low voice. Her belongings comprise two bags of clothes and a few books.

She was reluctant to tell her story. "I don't feel lonely. I consider everyone in the world my family," she said.

Homelessness has been around for the history of San Francisco, but the real turning point was in the late 1970s and early 1980s, when the cut to affordable housing resulted in a decrease of accommodation for low-income families, and de-industrialization in the US took away some of the stable union jobs, said Christopher Herring, a research fellow at the Center for Ethnographic Research of the University of California, Berkeley.

In addition, many veterans returning home from the Vietnam War were not able to assimilate into society, which was made worse by the crash of the mental health system during the Reagan administration that led to the elimination of service for people with mental illness, he said.

The continuation of the decrease in affordable housing makes homelessness particularly bad in the city, said Herring. "Some cities have the same level of poverty as San Francisco, but the housing is more affordable. So, you have less homelessness in their cities than in a place like San Francisco," he said.

"There's no federal funding going toward public housing and homelessness services. Until we see that, there's going to be mass homelessness in the United States," said Sam Lew, policy director of Coalition on Homelessness, an advocacy group in San Francisco.