Delhi's Duplicate Image Problem: How the Capital Stacks Up Against London, Seoul and São Paulo

Delhi's municipal and civic bodies are sitting on a documented backlog of duplicate and mismatched images spread across at least a dozen government-run digital platforms — a problem that wastes storage, misleads residents, and undermines trust in official portals at a time when the city is pushing hard to digitise services from ration card issuance to Metro route planning.

The issue has sharpened this year because three major Delhi government initiatives — the South Delhi Municipal Corporation's property tax portal, the Delhi Development Authority's housing scheme listings, and the unified Delhi One app backed by the Kejriwal administration — all expanded their photograph-based verification systems in 2025. Each platform independently ingested tens of thousands of property, identity, and infrastructure images. Without a shared deduplication protocol, the same photograph can appear in multiple records with different labels, different addresses, or different owner names attached to it.

What the City Is Doing — and Where It Keeps Stumbling

The Delhi government's IT Department piloted an automated image-matching tool across DDA servers in the second half of 2025, targeting roughly 40,000 property listing photographs that had been uploaded more than once. Officials working on the project — whose names have not been formally announced in any public statement — described the pilot internally as a proof-of-concept rather than a full rollout. No public audit results have been released to date.

Chandni Chowk's heritage documentation project, run jointly by the Archaeological Survey of India and the North Delhi Municipal Corporation, ran into the same obstacle in early 2026. Archivists cataloguing Old Delhi's 17th-century havelis and lane-frontages found that volunteer-uploaded photographs of the same structure had been indexed under at least three different street names — Khari Baoli, Nai Sarak, and Paranthe Wali Gali — creating conflicting visual records that complicated grant applications to the National Heritage City Development and Augmentation Yojana, known as HRIDAY.

The practical damage is real. A property listed twice with contradictory photographs on the SDMC portal can stall a sale for weeks while clerks manually reconcile the records. Residents in Dwarka Sector 12 and Rohini Phase 3 have reported delays of up to six weeks in property mutation certificates, though the municipal corporation has not officially attributed those delays to duplicate image data in any statement on record.

How London, Seoul and São Paulo Handle the Same Problem

London's Ordnance Survey adopted a mandatory image-hash deduplication standard across all local authority land registries in 2023, requiring every photograph submitted to planning portals to carry a unique SHA-256 hash before acceptance. The Greater London Authority reported in a 2024 audit — publicly available on the GLA website — that the system cut duplicate image entries by 78 percent in its first year of operation.

Seoul went further. The city's Smart City Data Hub, operational since 2022 and administered through the Seoul Digital Foundation, runs a real-time cross-database image reconciliation engine that flags duplicates within 90 seconds of upload. São Paulo's GEOSAMPA urban mapping platform, which covers the entire metropolitan area of roughly 22 million people, implemented a similar automated reconciliation layer in 2023 and now mandates that all city-contracted photographers submit images in standardised GPS-tagged formats that prevent duplicate registration at the point of capture.

Delhi has none of these end-to-end standards in place across its multiple civic bodies, which operate under a famously fragmented governance structure — the DDA, the three municipal corporations, the Delhi Urban Shelter Improvement Board, and the state government's own IT directorate each maintain separate image repositories with different metadata schemas.

The next concrete step on the official calendar is a joint technical committee meeting scheduled between the Delhi government's IT Department and SDMC for September 2026, which is expected to table a draft inter-agency image data standard. Whether that meeting produces a binding protocol — or another consultancy report — will determine whether Delhi closes the gap on Seoul and London or widens it. Residents or property owners dealing with duplicate-image delays in the meantime can file a Right to Information request to the relevant agency's Public Information Officer to formally flag a mismatch in their records, a process that carries a statutory 30-day response deadline under the RTI Act of 2005.