Enabling cleaner, greener communities with robust litter data

As a Public Sector Geospatial Agreement (PSGA) contractor for the Welsh Government, alongside collaborating with local authorities, Keep Wales Tidy is delivering a brand-new litter data methodology with the purpose of reducing litter in the environment. Through data analysis and monitoring trends, it is improving engagement with large body landowners who are responsible for cleansing and prevention. The methodology provides clear evidence for policy to aid in the eradication of litter and waste that will improve the safety and cleanliness of public spaces across Wales.

Keep Wales Tidy’s prior methodology focused on streets specifically, based on local authority intelligence. However, to expand the land types of survey locations (such as green spaces or retail sites) and better understand the extent of publicly accessible spaces, Keep Wales Tidy needed authoritative, definitive data.

Keep Wales Tidy adopted OS NGD (Ordnance Survey National Geographic Database) data to enable the identification of publicly accessible survey sites and strengthen its litter data analysis. In Keep Wales Tidy's pilot year (2025), its derived dataset had over 80,000 sites but through statistically significant sampling across Wales, this was reduced to a more manageable 5,466. Lower Super Output Areas (LSOAs), used in conjunction with the derived data, aided in a spatially targeted approach. Each year, 20% of these LSOAs will be surveyed and in five years 100% coverage will be achieved.

By using OS's Land Use Site and Transport Network datasets, the charity was able to identify open green spaces, retail sites, car parks, streets, paths and more.

Once survey sites were selected, surveyors would head into the field to gather data on amounts of litter present and the status of adverse environmental quality indicators (AEQIs), such as graffiti and dog fouling.

Integrating the OS NGD has led to improved systems and processes for the entire survey team. Any GIS desk work is now streamlined by benefiting from authoritative OS data. Out in the field the team have the data they need to accurately undertake their survey, whether that is in a park, a street, or on a path.

The new data and related systems have enabled surveyors to estimate more than 33.5 million pieces of litter across Wales in 2025 (equivalent to 10 items per person) and allowed teams to tackle 73% more locations. This evidence-led approach supports stronger environmental policy, and the new methodology has saved approximately 66 days of staff time.

When the charity’s new public data visualisation tools go live, local authorities and other stakeholders will be able to access near-live data during the survey period and use it to plan and prioritise cleansing activities in the right places.

This robust litter dataset will be pivotal in the introduction of key legislation, including Extended Producer Responsibility (EPR) for litter and Deposit Return Scheme (DRS) for drinks containers.

Ultimately, OS data is supporting Keep Wales Tidy to achieve a litter free Wales by 2030.