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

Delhi's municipal and heritage bodies are sitting on tens of thousands of digitised photographs, land records and urban planning documents riddled with duplicate image files — a data-quality crisis that is quietly distorting everything from property valuations in Shahjahanabad to environmental compliance filings along the Yamuna floodplain. The problem is not unique to the capital, but the scale of Delhi's administrative overlap, spanning the Municipal Corporation of Delhi, the Delhi Development Authority and the state government's own revenue directorate, means the duplication runs deeper here than in most comparable cities.

The issue has sharpened because Phase 4 of the Delhi Metro is generating fresh waves of geo-tagged site photography, environmental impact imagery and land-acquisition documentation. When the same photograph of a plot near Janakpuri West or Lajpat Nagar gets ingested by multiple agencies independently, each with its own naming convention, the result is a fractured archive that no single authority can audit end-to-end. Urban data specialists describe this as a compound problem: not just wasted server space, but active misinformation risk when duplicate images carry different metadata tags.

What Other Cities Are Doing Differently

London's Ordnance Survey completed a deduplication pass across its urban imagery database in 2024, using a perceptual hashing protocol that flags visually near-identical images even when file names differ. The Greater London Authority now runs quarterly reconciliation checks across all borough planning portals. Seoul's Smart City Division, operating out of the Digital Innovation Bureau in Jung-gu, went further in early 2025, mandating a single image repository for all construction and environmental monitoring photographs submitted to city hall — agencies that fail to comply face processing delays on permit applications. Mumbai's MCGM has piloted a similar centralised image registry for its coastal road project since November 2024, though civic activists there have raised concerns about access transparency.

Delhi has no equivalent unified system yet. The MCD's IT wing has been working since 2023 on a broader property records digitisation drive, but deduplication is listed as a secondary objective rather than a primary one. The DDA's online portal, meanwhile, operates on a legacy content management system that does not automatically flag repeated image uploads. Requests for comment to both bodies on their current image-management protocols were not responded to before publication.

The practical consequences show up in Old Delhi most visibly. In Chandni Chowk and the lanes around Jama Masjid, heritage documentation photographs commissioned by the Archaeological Survey of India overlap with MCD zonal office surveys and private contractor submissions, creating archives where the same crumbling haveli facade may be logged under three different case files with no cross-reference. A 2023 audit of urban heritage data quality conducted by researchers at the School of Planning and Architecture in New Delhi found that duplicate image rates in Old Delhi ward records ran as high as 34 percent in some sample datasets — a figure that complicates any attempt at systematic restoration planning.

What Needs to Happen Next

The pressure to act is building from two directions simultaneously. The National Geospatial Policy 2022, which came into effect progressively through 2024 and 2025, pushes all government agencies toward interoperable spatial data standards — a framework that logically requires deduplication as a precondition. At the same time, Delhi's own air quality emergency response infrastructure depends on accurate, unduplicated photographic evidence when agencies cross-check pollution sources near industrial clusters in Bawana and Narela.

Advocates for digital governance reform argue the fix is not technically complex. Perceptual hashing tools are open-source and widely available. The harder challenge is institutional: getting the MCD, DDA, the Delhi government's Revenue Department and central agencies like the ASI to agree on a shared protocol and a single point of accountability. Seoul managed it with a firm mayoral mandate and a hard deadline. London did it by tying compliance to planning fee revenue. Mumbai is testing a middle path. Delhi, with its uniquely contested division of authority between an elected state government and a lieutenant governor's office, has not yet found the political arrangement that would allow any one body to impose the same discipline.

For residents, the most immediate practical advice is simple: if you are submitting property documentation, environmental NOC applications or heritage conservation proposals to any Delhi agency, save timestamped copies of every image you upload and note the file reference number. Until a unified system exists, your own records may be the only reliable check against the duplication problem swallowing your paperwork.