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

Delhi's municipal digital records contain thousands of duplicate property photographs, street-level images and heritage documentation files that no one has systematically cleaned up. The Municipal Corporation of Delhi, which absorbed three legacy bodies in a 2022 merger, inherited overlapping image databases from the former South, North and East Delhi municipal corporations — and the deduplication backlog has been growing ever since.

This matters now because the MCD is mid-way through a push to digitise property tax assessments across all 12 zones of the capital, a programme tied directly to Chief Minister Arvind Kejriwal's administration's broader Smart Delhi agenda. Duplicate images slow down assessments, inflate storage costs and, in several documented cases handled through the MCD's helpdesk portal, have caused incorrect properties to be flagged for notice because an officer matched the wrong photograph to a plot record.

Where Delhi Stands Against Comparable Cities

London's Ordnance Survey completed a major duplicate-image audit of its National Geographic Database in 2023, removing more than 1.4 million redundant asset photographs from public land records — a process that took 18 months and involved automated hash-matching software. Seoul's Smart City Division, operating out of the Digital Innovation Hub in Sangam-dong, deployed an AI-assisted deduplication pipeline for its urban infrastructure image library in late 2024, cutting storage overhead by roughly 30 percent, according to figures the Seoul Metropolitan Government published on its open-data portal in March 2025. Mumbai, the closest Indian parallel, tasked the Brihanmumbai Municipal Corporation's IT cell with a similar exercise in 2024 under its MCGM Digital Transformation roadmap, targeting ward-level property image archives first.

Delhi has no equivalent published programme. The MCD's IT department, based at the corporation's headquarters on S.P. Mukherjee Road near ITO, has not released a deduplication timeline or allocated a separately ring-fenced budget line for the work, based on budget documents reviewed for the financial year 2025-26. That absence of a formal framework is what separates Delhi from the cities it is most often compared with.

The Delhi Development Authority faces a parallel problem in its housing records. The DDA manages image archives for tens of thousands of flats across schemes in Dwarka, Rohini and Vasant Kunj, and residents filing resale documentation frequently report being sent back because a property photograph on file does not match the current unit — often because an older, duplicate image superseded a newer upload without any version-control mechanism in place.

The Cost of Inaction

Storage is not the only issue. Under India's Digital Personal Data Protection Act, which came into force in 2023, images containing identifiable individuals — faces captured incidentally during street or property surveys — require either consent or deletion. Duplicate images compound compliance risk: every copy of a non-compliant photograph is itself a separate liability. Legal technology specialists note that municipal bodies have until December 2026 to demonstrate data minimisation practices under draft rules issued by the Ministry of Electronics and Information Technology.

The National Informatics Centre, which provides backend infrastructure for multiple Delhi government portals including the e-District platform at edistrict.delhigovt.nic.in, has piloted perceptual hashing tools for document deduplication in other states. Whether that tooling is extended to MCD's image repositories depends on a procurement decision that has not yet been publicly announced.

For Delhi residents, the practical steps are narrow but real. Anyone submitting property or planning documents through the MCD's online portal at mcdonline.nic.in should upload images in JPEG format with file names that include the property ID and date of capture — a naming convention that makes manual deduplication significantly easier for assessors. Those who have previously uploaded photographs for tax or resale purposes and later received conflicting correspondence are entitled to request a file review under Right to Information provisions, citing Section 4(1)(b) of the RTI Act, which obligates public bodies to maintain accurate records. As the December 2026 compliance deadline approaches, the gap between what Delhi's civic bodies have planned and what cities like Seoul and London have already executed will become harder to paper over.