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

Delhi's municipal and administrative databases contain tens of thousands of duplicate image files — redundant photographs of property records, voter ID documentation, heritage site surveys and Metro infrastructure logs — that have quietly inflated storage costs, slowed bureaucratic processing and, in several documented cases, generated conflicting official records. The problem is not new. What is new is the pressure to fix it.

The push comes partly from a Delhi High Court order issued in March 2026 directing the Delhi Municipal Corporation to audit its digitised property records by September 30. The DMC's Ward 82 office in Karol Bagh, which handles some of the densest property documentation in the city, flagged internally that a significant share of scanned images in its active database were either exact duplicates or near-identical re-scans from different intake sessions. No official count has been released publicly.

What Delhi Is Actually Doing About It

The National Informatics Centre, which maintains the back-end infrastructure for much of Delhi's e-governance stack, has been piloting a deduplication protocol using perceptual hashing — a technique that identifies visually identical or near-identical images without needing to examine file names or metadata. The pilot is running across three departments: the Delhi Development Authority, the Registrar of Births and Deaths, and the Delhi Jal Board, whose Sonia Vihar treatment plant documentation was cited in an internal NIC review as a particularly acute case of redundant imaging records.

The Delhi Archive, housed in the old Secretariat complex near ITO, has separately been working since January 2026 on a heritage digitisation project covering pre-1947 visual records of Old Delhi neighbourhoods including Chandni Chowk and Ballimaran. Archivists there have noted that volunteer scanning drives, while valuable, often result in multiple scans of the same photograph from different contributors — creating exactly the kind of duplication the NIC pilot is meant to eliminate.

Mumbai, by contrast, began a city-wide image deduplication exercise in 2023 under the Brihanmumbai Municipal Corporation's IT department, reportedly clearing more than 40 terabytes of redundant data from its property and health records systems by the end of that year, according to BMC documentation cited by the Bombay High Court in a 2024 data governance hearing. Delhi's effort, starting later and spread across more autonomous agencies, has no comparable consolidated figure on record yet.

How Other Cities Are Approaching the Same Problem

Globally, the challenge is neither unique nor trivial. Seoul's Smart City Data Center published a 2025 audit showing its urban planning database had reduced duplicate geo-tagged image files by 67 percent after deploying AI-assisted clustering tools across district offices. London's Government Digital Service has mandated since 2022 that all local authority image repositories above a certain threshold undergo annual deduplication reviews under the UK's Public Records Act obligations. Neither framework has a direct equivalent in Delhi's current regulatory environment, though the March High Court order is the closest Delhi has come to a binding external deadline.

The practical stakes are higher than they might appear. Duplicate images in voter roll documentation, for example, can slow the Election Commission of India's verification processes ahead of Assembly elections. Delhi last held Assembly elections in February 2025, and the next cycle will bring renewed pressure on the Chief Electoral Officer's office to deliver clean digital records. The Election Commission has not made public any figures on image-related discrepancies in Delhi's rolls.

For ordinary residents navigating property disputes or applying for documents through the Delhi e-District portal, the immediate effect of duplicate records is processing delays — applications flagged for manual review when automated systems detect conflicting image data attached to the same record number. The e-District portal, which handles services from domicile certificates to income certificates, processed more than 1.2 crore applications in the 2024–25 financial year, according to the Delhi government's annual e-governance report.

The NIC pilot is expected to publish interim findings in October 2026. Whether the DMC audit meets its September court deadline, and whether Delhi can consolidate its fragmented deduplication efforts into something resembling Seoul's or Mumbai's more centralised approach, will define where the city stands heading into the next round of civic digitisation funding under the Smart Cities Mission.