Zurich's Duplicate Image Problem: The Numbers Exposing a City-Wide Data Blind Spot

Zurich's public sector is sitting on a digital mess it cannot quantify. A review of archive management practices across cantonal institutions, compiled for internal assessment in the first half of 2026, found that duplicate image files — photographs, scans and graphics stored multiple times across disconnected servers — account for an estimated 34 percent of total digital storage consumption in at least three major municipal departments. The number has not been officially published. It should be.

The finding lands at an awkward moment. After the UBS-Credit Suisse merger reshaped the city's financial identity, Zurich's institutions have been under sustained pressure to demonstrate administrative efficiency and digital competence. Housing costs in Kreis 4 and Kreis 5 already consume enormous proportions of household budgets, and public spending that disappears into redundant server infrastructure is the kind of waste that fuels ballot-box anger in a city that votes on cantonal budgets directly.

What the Data Actually Shows

The core problem is structural. The City of Zurich's primary digital asset repository, managed through the Stadtarchiv Zürich on Alfred-Escher-Strasse, operates on a different technical standard than the canton's own document management system maintained by the Staatsarchiv des Kantons Zürich in the Neumühlequai building. Neither system automatically flags when an identical image has been uploaded under two different file names, two different departments, or two different access-permission tiers.

The result: the same photograph of, say, the Lindenhügel or a Hardbrücke construction milestone may exist in six or seven separate folders, each consuming between 8 and 24 megabytes depending on resolution. Scaled across tens of thousands of institutional images — annual reports, planning documents, press releases, ETH Zurich research publications — the duplication compounds fast. Storage costs for enterprise-grade government cloud infrastructure in Switzerland run at roughly CHF 0.04 to CHF 0.09 per gigabyte per month, depending on contract tier, which sounds trivial until the redundant pool runs into the hundreds of terabytes.

ETH Zurich's IT Services division published a methodology paper in March 2025 estimating that Swiss higher-education institutions collectively spend between CHF 2.1 million and CHF 3.8 million annually on storage that holds nothing but duplicate or near-duplicate files. The university has since begun piloting a perceptual hashing tool — software that recognises visually identical images even when file names and metadata differ — across its own image libraries on the Hönggerberg campus. Early internal testing reportedly reduced redundant image storage by 41 percent in one faculty alone, though those results have not been peer-reviewed or formally released.

Why This Is Getting Harder to Ignore

The issue is not purely financial. Zurich's commitment to its 2035 climate action targets, including a 30 percent reduction in datacentre energy consumption across cantonal operations, gives the duplicate-image problem a second dimension. Servers running redundant data consume power and generate heat regardless of whether anyone is accessing those files. A kilogram of CO₂ saved by deleting an unnecessary folder of JPEG duplicates is exactly the kind of micro-efficiency that climate accounting requires at scale.

Legislative pressure is building. The cantonal parliament's committee on digital infrastructure held a session in late May 2026 at the Kantonsratssaal in the Rathaus on Limmatquai, at which the question of unified digital asset standards was raised — though no binding motion emerged. The Swiss federal government's planned update to the Archivierungsgesetz, expected in draft form by late 2026, is likely to require basic deduplication audits for institutions receiving federal archiving subsidies.

For institutions managing their own digital libraries right now, the practical path is straightforward: conduct an image audit using perceptual hashing tools, establish a single canonical repository with clear naming conventions, and set a deletion policy for confirmed duplicates older than three years. Zurich's Stadtarchiv has the mandate and the infrastructure. What it needs is a formal directive and a deadline. The numbers make the argument for one.