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

Delhi's municipal and state government databases contain tens of thousands of duplicate images — photographs of the same property, road stretch, or public facility uploaded multiple times across competing portals — creating a bureaucratic tangle that wastes storage, slows processing and, in several documented cases, has delayed the issuance of property tax assessments and building permits in areas from Shahdara to Dwarka. The problem is not new. But a quiet push within the Delhi government's Information Technology department, running since January 2026, to audit and purge redundant image files from the MCD's online property records system has brought it back into public focus.

The timing matters. Delhi is mid-way through a broader digitisation drive tied to the Phase 4 Delhi Metro corridor approvals, which require updated geo-tagged photographic records of land parcels along the Janakpuri West–RK Ashram and Tughlaqabad–Aerocity alignments. When duplicate images exist in the same database — sometimes three or four versions of a single lane in Lajpat Nagar or a plot boundary in Rohini — automated verification scripts flag conflicts, stalling approvals. Each stall, according to the general logic of such systems, can push a file back weeks in a queue already under pressure from thousands of pending applications.

What Mumbai and London Are Doing Differently

Mumbai's Brihanmumbai Municipal Corporation launched a centralised image deduplication protocol in March 2025, contracting the work to the National Informatics Centre under a framework that required all civic portals to route property photographs through a single hash-matching server before storage. The approach reduced Mumbai's duplicate image count by an estimated 34 percent within six months, according to a progress note published by the NIC in October 2025. London's Ordnance Survey has operated a similar automated deduplication layer across its geospatial datasets since 2022, using perceptual hashing algorithms that can identify near-identical images even when file formats differ. São Paulo's municipal government, facing its own cadastral backlog in 2023, embedded deduplication checks directly into the upload interface of its Nota Fiscal Eletrônica portal, catching duplicates at the point of entry rather than in post-processing cleanup.

Delhi's approach has been more fragmented. The Municipal Corporation of Delhi, the Delhi Development Authority and the state government's revenue department each maintain separate image repositories with no shared deduplication layer between them. A property in Karol Bagh, for instance, may have photographs sitting in all three systems simultaneously, with no automated cross-check to flag the overlap. An IT department audit summary circulated internally in April 2026 — details of which have been reported by technology policy researchers — described the situation as a legacy problem compounded by successive rounds of portal migration between 2018 and 2023, each of which imported old image libraries without cleaning them first.

The Cost of Inaction and What Comes Next

Storage costs are one dimension. Cloud hosting for large unstructured datasets is not cheap, and municipal budgets in Delhi have historically been stretched. But the more consequential cost is in processing time. Property mutation applications, which residents of colonies from Uttam Nagar to Mayur Vihar file in large volumes every quarter, are reviewed partly on the basis of photographic evidence. When a reviewer's interface returns multiple conflicting images for the same address, manual resolution is required — a step that adds, on average, an estimated two to three working days per file according to general benchmarks used in e-governance assessments.

The Delhi government's IT department has indicated that a request for proposal for a unified image management platform — one that would span MCD, DDA and revenue department repositories — is under preparation. If issued before the end of the third quarter of 2026, a functional system could be operational by mid-2027, which would align with the projected completion window for Phase 4 Metro land record verification. In the meantime, residents filing property-related applications at civic centres in Rohini Sector 13 or the Pragati Maidan area are being advised by helpdesk staff to submit freshly dated photographs alongside their documents, reducing the chance that an old duplicate on file will trigger a conflict flag. It is a workaround, not a fix — but in Delhi's administrative machinery, workarounds have a way of lasting longer than anyone intends.