CMDA or DTCP: which planning authority governs your project

The division, in outline

Tamil Nadu has two principal planning regimes for building approval. The Chennai Metropolitan Development Authority is the planning authority for the Chennai Metropolitan Area. The Directorate of Town and Country Planning, through its local planning authorities, covers the rest of the state.

Below both sits the local body — the corporation, municipality, town panchayat or village panchayat — which issues the building licence once planning permission is granted. Planning permission and building licence are two separate approvals from two different offices, and having one does not imply the other.

The common error is treating "CMDA approved" or "DTCP approved" as a complete description of a plot. It describes the planning approval for a layout. Whether the specific plot also has local body approval, and whether the building you intend is permissible under the applicable development control rules, are separate questions.

The boundary is a jurisdiction, not a city limit

The Chennai Metropolitan Area is substantially larger than the Chennai Corporation area, and it extends into parts of the surrounding districts. A plot that is nowhere near the city can fall inside it, and a plot with a Chennai address can fall outside the corporation while remaining inside the metropolitan area.

The jurisdiction has also been expanded over time. A plot approved under one regime years ago may now sit inside a different one, which affects what is permissible for a new development on it even though the existing approval remains valid.

Because the boundary moves and the consequences of assuming are large, the jurisdiction should be confirmed against the current notified area for the specific survey number before purchase — not inferred from the postal address or from what the neighbouring layout was approved under.

What actually differs between the two

Both regimes govern the same categories of thing, but the specifics are set separately and are not interchangeable.

• Floor space index and coverage — the permissible built-up area for the same plot size can differ between regimes and between zones within a regime.
• Setbacks and height — tied to plot size, road width and the building category, with different tables in each set of rules.
• Road width requirements for layout approval, which frequently determine whether a plot is developable at all.
• Category thresholds — what counts as an ordinary building versus a special or multi-storey building, which changes the approving authority and the scrutiny applied.
• Fees, scrutiny timelines and the documents required at submission.

What to establish before buying

Five questions, in this order. Each one can end the transaction, so asking them in order saves the cost of the later ones.

• Which planning authority has jurisdiction over this survey number, as currently notified.
• Is the land classified for the use intended — residential, commercial, industrial — under the applicable master plan or detailed development plan.
• Does the approach road meet the minimum width for the development intended, and is it a recognised public road.
• Is the layout itself approved, and does the approval cover this specific plot number — an approved layout does not mean every plot in it is regularised.
• Are there restrictions specific to the location — CRZ, water body buffers, aquifer or catchment restrictions, airport height limits, heritage or defence proximity.

Unapproved and regularised plots

A substantial amount of land in Tamil Nadu is in unapproved layouts, and schemes to regularise them have run at various points. A plot sold as "regularised" or "applied for regularisation" is not the same as an approved plot, and the difference shows up when a building plan is submitted or a loan is sought against it.

Whether a given plot can be regularised, under which scheme, and what it costs are specific to the plot and to whatever scheme is currently open. That is a question for a local advocate who does title work in that taluk, not one to resolve from general guidance.

A caution on specifics

Development control rules, jurisdiction boundaries, FSI figures, fee structures and regularisation schemes all change, sometimes substantially, and they vary by zone within a single authority.

This guide deliberately gives none of those numbers. It describes which questions determine the answer and who holds it. For a specific plot, the sources are the current development control rules of the applicable authority and a licensed surveyor or architect who files in that jurisdiction regularly.