Dhaka's Duplicate Image Crisis: The Key Decisions That Will Shape the City's Digital Records

Dhaka's two city corporations are facing a decision point over how to handle tens of thousands of duplicate images lodged inside their joint civic digitisation database, a problem that has quietly undermined the reliability of property tax records, land-use surveys, and citizen service files accumulated since the National Digital Service Drive launched in January 2024.

The issue matters now because both Dhaka North City Corporation (DNCC) and Dhaka South City Corporation (DSCC) are in the middle of expanding their digital infrastructure ahead of a July 2027 deadline set under the Bangladesh National Digital Architecture Framework. Duplicate images — multiple scans of the same document filed under different citizen IDs — create cascading errors in automated systems, inflating record counts and, in some cases, flagging legitimate property owners as having inconsistent documentation. Resolving the backlog before the expansion proceeds is not optional; it is a prerequisite for the new system to function correctly.

The problem has surfaced most visibly in two areas. In Mirpur, where DNCC ward offices digitised tens of thousands of holding tax files between February and October 2024, field staff scanning physical documents at the Mirpur-10 civic service centre used a batch-upload protocol that did not automatically reject files already in the system. In Lalbagh, under DSCC jurisdiction, a parallel drive to digitise building permit photographs produced a similar result when scanning contractors submitted image sets without deduplication checks. Rajuk, the capital development authority, has separately flagged that its own land parcel image archive — hosted at its Agargaon headquarters — contains an estimated overlap with the city corporation databases, though the full scope of that overlap has not been formally audited.

Three Options on the Table

City technology officials are weighing three broad approaches. The first is an automated deduplication sweep using perceptual hashing, a technique that compares image fingerprints rather than file names and can process large archives quickly. The technology is well-tested and was used by Kolkata Municipal Corporation in a comparable exercise in 2023, reducing its civic image database by roughly 18 percent. The catch in Dhaka's case is that neither DNCC nor DSCC currently has the server capacity to run such a sweep without temporarily taking down citizen-facing portals — a politically difficult move given the volume of holding tax payments processed online each month.

The second option is a manual review programme targeting only the highest-risk file categories: property transfer documents and building permits. This would be slower but would allow portals to stay live. Ward-level data officers at offices including the Gulshan-2 civic centre and the Demra area office would carry out the review using a checklist protocol, cross-referencing against the original physical registers. A manual review of this kind, limited to roughly 40,000 priority files across both city corporations, could realistically be completed within six months if additional contract staff are brought on.

The third option — and the one carrying the most long-term significance — is to pause further digitisation expansion until a unified deduplication standard is agreed upon across DNCC, DSCC, and Rajuk. That standard does not currently exist. Each agency has adopted its own file-naming convention and metadata schema, which is precisely how the duplication problem compounded across institutions in the first place.

What Comes Next

A cross-agency technical committee is expected to meet at the ICT Division offices on Agargaon Road later this month to present a formal recommendation to the Local Government Division. That recommendation will set the approach for at least the next 18 months. Civic technology researchers at BRAC University's Institute of Governance Studies have been monitoring the digitisation rollout and are expected to submit a review paper ahead of that meeting, though their findings have not yet been made public.

For ordinary Dhaka residents — particularly the estimated 1.2 million holding tax payers registered across the two city corporations — the practical stakes are real. Duplicate image records have already caused delays in property transfer clearances at select ward offices in Mohammadpur and Demra, with some applicants waiting three to four weeks longer than the stated 10-day processing window. The decision made this month will determine whether that wait gets shorter or significantly longer as the system scales up.