Officials in Lagos, Nigeria, were facing a dilemma.  

It was the early 2020s, and the city of 22 million was being overwhelmed by plastic pollution. Water sachets and takeaway containers were clogging canals, littering streets and bursting from landfills. 

But as evident as the problem was, city officials needed to know exactly how much plastic pollution Lagos was generating. The data that would be key to developing policy solutions. So, the city partnered with the United Nations Environment Programme (UNEP) and the UN Human Settlements Programme (UN-Habitat) to conduct the first-ever audit of its waste. 

The results were surprising. Some 34 kg of plastic waste per person per year was leaking into Lagos’ water system. That’s the equivalent of every Lagos resident throwing 10 plastic water bottles into waterways every single day.  

The revelations, Lagos officials say, led the Lagos State Government in 2024 to ban all single-use food containers made from polystyrene foam, also known as styrofoam.

“The data convinced us to stand up with our political will,” says Tokunbo Wahab, Environment and Water Resources Commissioner in the Lagos State Government. 

Lagos is one of a growing number of cities that are attempting to use data, often painstakingly gathered through dumpsite visits and household surveys, to rein in plastic waste and end plastic pollution. The research has spawned bans on single-use plastics and new investments in waste management infrastructure. Experts say measures like those are crucial for curbing plastic pollution, which they called a growing threat to the environment. 

“Worldwide, there are yawning data gaps and reliability issues when it comes to plastic waste and plastic pollution,” says Sinikinesh Jimma, head of UNEP’s Marine and Freshwater Branch. “Plugging those is crucial for developing evidence-based policies and countering what is a mushrooming crisis.” 

As widespread as plastic waste and pollution are, there’s a dearth of data about them, says Jimma. That makes it difficult for government officials to justify pricey investments in waste management infrastructure, like recycling centres. 

But efforts are underway to arm local and national officials with the data they need. UNEP and UN-Habitat, for example, have developed what’s known as the Waste Wise Cities Tool, a series of guidelines that help cities gauge how much plastic waste they’re generating.  

The tool underpinned an audit in the bustling Kenyan port city of Mombasa. There, officials sifted through the trash of dozens of volunteer families, both high- and low-income, cataloguing how much plastic and other waste it contained. Surveyors also visited landfills, charting the volume of plastic waste and recording whether it came from formal or informal collectors. 

The research showed that only about 50 per cent of Mombasa’s waste was collected and just 5 per cent was recovered in 2020. The data helped the city attract financing for a plastic waste sorting plant. Two international aid agencies are now weighing a large-scale investment that would improve Mombasa’s entire municipal solid waste system. 

The waste measurement guidelines co-developed by UNEP are “providing the scientific data that we are using to develop bankable project proposals, and mobilize funds and private sector investment,” said Francis Thoya, Deputy Governor of Mombasa County. 

Experts say the lack of waste- and pollution-related data globally is part of a larger plastic information gap. Few comprehensive metrics cover things like the production of plastic polymers, and how plastic products are designed, manufactured and recycled. 

“A holistic understanding of the entire life cycle of plastics, from production to disposal, is necessary to develop comprehensive strategies that effectively counter plastic pollution,” says Jimma. 

Waste-related data from Mombasa, and other cities, is being piped into the Global Plastics Hub, a platform developed by UNEP and backed by the Global Partnership on Plastic Pollution and Marine Litter. The hub, which has been funded by the governments of Japan, Norway and the United States of America, is designed to be a one-stop shop where government officials – and others – can track 80 plastic-pollution-related indicators.

The portal is among the most comprehensive platforms of its kind in the world. In-depth country dashboards track how much plastic countries trade, how they manage plastic waste and what policies they have to counter plastic pollution. It’s designed to help countries make more informed decisions about how to address plastic pollution. 

This year’s World Environment Day, an annual celebration of the Earth hosted by UNEP, will focus on solutions to end plastic pollution. It comes as global plastic waste – which is often linked to pollution – is set to reach nearly 1 billion tonnes a year by 2060.  

“Many cities are running out of time to address this problem,” says Jimma. “It’s so important for municipalities to plug data gaps and make headway on reducing plastic pollution.”

The world generated around 400 million tonnes of plastic waste in 2024, according to the Organisation for Economic Co-operation and Development. That number is expected to nearly triple within the next 25 years, with some of the steepest rises coming in developing countries, especially in the Africa and Asia-Pacific regions. If current trends hold, much of that plastic will end up in rivers, lakes and the ocean.