The number of people living without access to safe sanitation in cities across the world is on the rise, and the situation is looking worse than previously thought, according to a new report. 

“Untreated and Unsafe: Solving the Urban Sanitation Crisis in the Global South,” released by the World Resources Institute (WRI) on Wednesday, closely examines how urban areas in low to middle-income countries manage waste. On average, the majority of sewage and fecal sludge is improperly managed in 15 cities in Asia, Africa, Latin America, and the Carribean, the study found. 

"For too long, urban policymakers and governments have turned a blind eye to the problem of untreated human waste in cities, and pretended, because it was handled by households and out of sight, that the problem was taken care of," Victoria Beard, co-author of the study and fellow at WRI Ross Center for Sustainable Cities, said in a statement released to U.S. News. "But the fact is that this presents a huge public health risk as well as a drag on the economy."

Untreated human 💩 exposes urban residents & the environment to huge risks and costs around $223 billion a year. Read more in our new #CitiesForAll paper on actions cities can take to leave no behind behind ➡️ https://t.co/cUMTqpxgrXpic.twitter.com/Ky0jarz86S

— World Resources Inst (@WorldResources) December 18, 2019

Access to safely managed sanitation means human waste is properly contained, transported, treated, reused, or disposed of, but a growing number of cities don’t provide these services to residents.

Almost two-thirds of human waste in 15 major cities is unsafely managed, with access to safe sanitation lowest in South Asian and sub-Saharan African cities, WRI’s research showed. The number of urban residents who lack safely managed sanitation has gone up over the years, from 1.9 billion in 2000 to 2.3 billion in 2015. On average, only 62% of sewage and fecal sludge in the cities studied is safely managed during the sanitation process. 

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Some cities such as Caracas, Venezuela; Colombo, Sri Lanka; and Karachi, Pakistan, don’t manage human waste at all. In many of the cities examined, residents dump human waste and household wastewater into storm drains or nearby waterways.

Poor sanitation can lead to the transmission of disease, stunting, malnutrition, and limit economic opportunities. Women are often affected by sanitation issues more than men because they are usually responsible for handling household duties, the report said.

While governments and leaders are taking action to address sanitation in urban communities, the report authors say there needs to be more follow up. In some neighborhoods in Nairobi, Kenya, pit latrines are being counted as improved sanitation despite improper use. Low-income households can’t afford to pay to have their pit latrines emptied properly so they opt for cheaper services and their waste ends up emptied somewhere that contaminates local water sources, or not at all, according to the report.

The report urges governments and city decision-makers to invest in long-term sanitation infrastructure and enforce effective regulations. The researchers say that cities should extend sewer networks to households and communal toilets. For areas without a sewer system, cities are recommended to regulate affordable sanitation options like septic tanks and pit latrines in people’s homes.