Illegal and unauthorised construction in redevelopment — how to keep your society safe
Building beyond the sanctioned plan can block your OC and invite demolition. Here is how to spot the warning signs early and protect every member.
Unauthorised construction in redevelopment means your developer has built something the municipal corporation never sanctioned — extra floors, more built-up area than the approved Floor Space Index (FSI, the ratio that fixes how much can be built on a plot), or structures that eat into open spaces and set-backs (the gaps that must be left around a building for light, air and fire access). It matters because the rulebook is strict: under the Development Control and Promotion Regulations 2034 (DCPR 2034), which govern construction in Greater Mumbai, every building must follow its sanctioned plan, and any work that goes beyond it can be refused an Occupancy Certificate (OC), penalised, or even demolished. This guide explains, in plain language, what counts as unauthorised work, the warning signs to watch for, the protection the law already gives you, how to check the sanctioned plans yourself, and the concrete steps that keep your society safe.
What counts as unauthorised construction
Every redevelopment is built against a set of approvals — the IOD (Intimation of Disapproval, the corporation's first set of conditions), the Commencement Certificate (CC, permission to start building) and the sanctioned plans that fix the height, layout and permissible built-up area. Construction becomes unauthorised the moment it strays beyond those approvals without a fresh, amended sanction. In reported cases the common forms include:
- Adding extra floors or flats beyond the sanctioned number.
- Consuming more FSI than the plot legally supports, or claiming Transfer of Development Rights (TDR) or premium FSI that was never actually loaded and approved.
- Encroaching on marginal open spaces and set-backs — the mandatory gaps around the building.
- Building over recreation ground, podium or open space meant for members' common use.
- Converting stilt parking, refuge floors or common amenities into saleable flats.
- Quietly building differently from the approved plan and hoping to "regularise" it afterwards.
Unauthorised work rarely appears as one dramatic act. Because most members are living in rented transit homes during construction and cannot watch the site every day, small deviations often go unnoticed until the structure is already up. By then, removing an illegal floor is far harder — and far more painful — than preventing it in the first place. Our guide on transit and construction explains how to keep a watchful eye even while you are away.
Why a deviation puts every member at risk
The developer may profit from the extra flats, but the risk sits squarely with your society. An unauthorised structure can invite a stop-work notice or a demolition order, and it almost always blocks the OC — the single most important document for your new building.
No Occupancy Certificate, no peace of mind
An OC certifies that the building is complete exactly as approved and is fit for legal occupation. Under DCPR 2034, unauthorised construction is a direct ground to deny the OC. Without it, occupying the building is technically illegal: banks hesitate to sanction home loans against the flats, buyers walk away, property tax and water charges can be levied at penal rates, and utility connections may only ever be temporary. Members can end up owning a flat they cannot easily sell, mortgage or insure — a heavy price for a deviation they never agreed to. Our page on the risks of no Occupancy Certificate sets this out in detail.
Warning signs, and how to protect your society
You do not need to be an engineer to catch most problems. Watch for these signs on and around the site, and act on each one early — in writing, and as a committee rather than as a lone worried member.
| Warning sign on site | How to protect your society |
|---|---|
| More floors or flats rising than the sanctioned plan shows | Obtain the CC and approved plans, count the sanctioned floors, and raise any gap in writing with the committee and your consultant. |
| The building touches the compound wall, with little or no gap around it | Check the set-backs and open space marked on the approved layout; report encroachment before the next slab is cast. |
| Stilt parking, refuge floors or common amenities being converted into flats | Compare against the approved plan; these areas are protected and cannot be sold. Read our guide on refuge area and fire safety. |
| Podium, recreation ground or garden being built upon | Match against the approved amenity layout; open space is legally protected — see the open space & recreation podium judgment. |
| Developer avoids sharing the IOD, CC or sanctioned plans | Insist in writing under your agreement; if still refused, apply under RTI to the corporation for certified copies. |
| Design or specifications changing mid-project without a members' vote | RERA Section 14 requires the written consent of two-thirds of allottees for any change — withhold consent until it is properly sought. |
| "We will regularise it later" assurances | Treat this as a red flag. Regularisation is discretionary and never guaranteed — insist everything is sanctioned before it is built. |
| Possession offered but no OC produced | Do not take possession or release the final corpus instalment until the OC is shown. |
The rules that already protect you
Two provisions are especially useful for a society trying to keep its redevelopment honest.
- DCPR 2034 — build only as sanctioned. The regulations require construction in Greater Mumbai to follow the sanctioned plan, keep mandatory open spaces and set-backs, and obtain an OC before occupation. Unauthorised construction risks penalties, demolition of the illegal portion and denial of the OC. Read DCPR 2034 explained for a plain-language overview.
- RERA Section 14 — no changes without your consent. Section 14 of the Real Estate (Regulation and Development) Act, 2016 says a promoter cannot alter the sanctioned plans, layout or specifications of a project without the written consent of at least two-thirds of the allottees (the members and flat buyers). A quiet deviation that adds flats or shrinks amenities is exactly the kind of change this section is meant to stop. Courts have upheld this — see our note on why changing sanctioned plans needs consent. Section 14(3) of the same Act also makes the promoter liable to fix structural or workmanship defects reported within five years of possession.
Together these mean that a developer cannot lawfully build beyond the plan, and cannot lawfully change the plan behind your back. Both give your society a firm footing to object.
How to verify the sanctioned plans yourself
Prevention starts with holding the right documents and, ideally, one independent professional on the society's side.
- Get the approved documents. Ask the developer, in writing, for the IOD, CC and the latest sanctioned plans. A well-drafted development agreement already entitles the society to these.
- Cross-check on MahaRERA. A registered project must upload its approved plans, sanctioned FSI and floor details on the MahaRERA portal — compare them with what is actually rising on site.
- Understand your entitlement. Use our FSI calculator to get a feel for how much your plot can legally support, so an inflated claim stands out.
- Appoint an independent eye. A society-appointed architect or Project Management Consultant (PMC) can audit the site against the sanctioned plan at every slab. Our tender & agreement review service helps you build this safeguard into the contract from the start.
- When in doubt, apply under RTI. Certified copies of the approved plans can be obtained from the municipal corporation's Building Proposal department, independent of the developer.
Concrete steps to protect your society
A demolition notice is far more expensive than prevention. A few disciplined steps keep your redevelopment on the right side of the law:
- Read the agreement first. A sound development agreement fixes the sanctioned area, floor count and timelines, and makes any deviation a clear breach. See red flags in a development agreement.
- Appoint a PMC before work starts and give them a written mandate to check construction against the sanctioned plan at every stage.
- Insist on approved copies of the IOD, CC and plans, and keep a full society set safe with the committee.
- Guard the open space. Protect your recreation ground, set-backs and podium; these belong to the members, not to the developer's sales book.
- Withhold consent to changes unless the two-thirds vote required by RERA Section 14 has genuinely been taken, and the amended plan is sanctioned.
- Never accept possession without the OC, and hold back the final corpus instalment until it is produced.
- Work from a checklist. Our redevelopment checklists give your committee a simple, step-by-step way to stay on top of every approval.
How to raise a complaint
If you suspect a deviation, act early and keep everything on paper. A committee acting together carries far more weight than a single member.
- Put your concern in writing to the Building Proposal (BP) department of your local ward office, addressed to the Executive Engineer, with the plot's survey or CTS number and a clear description of the suspected deviation.
- Ask the corporation to inspect the site and issue a stop-work notice if the work is beyond sanction. In Mumbai this is the BMC (MCGM); elsewhere it is your city's own municipal corporation.
- Rely on DCPR 2034: unauthorised construction can attract penalties, demolition of the illegal portion and denial of the OC, and the planning authority has powers to act.
- Keep dated copies of every complaint, acknowledgement and reply. If the ward office does not act, escalate in writing to the Deputy or Additional Municipal Commissioner.
- Send a copy of the complaint to the developer on the society's letterhead, so there is a clear record that the society formally objected.
Your legal remedies
Complaining to the corporation is the first step, but your society has other remedies if a developer builds illegally:
- MahaRERA: if the project is RERA-registered, the society or members can complain under Section 31 of RERA about construction that departs from the sanctioned plans or from Section 14.
- Consumer Protection Act, 2019: handing over flats without a valid OC, or that do not match what was promised, can be pursued as a deficiency in service before the consumer commission.
- Criminal law: where there is deliberate deception, the offences of cheating under Section 318 and criminal breach of trust under Section 316 of the Bharatiya Nyaya Sanhita, 2023 (which replaced the Indian Penal Code, 1860) may apply, and the society can file an FIR or police complaint. See our note on why builder cheating can be criminal.
- Co-operative forum: disputes between a society and its developer can also be taken to the Co-operative Court under Section 91 of the Maharashtra Co-operative Societies Act, 1960.
Illegal construction is not something a society has to accept quietly. Caught early — with the right documents, an independent professional and a united committee — most deviations can be stopped before they harden into a demolition risk. If you would like a plain-language second opinion, register your society and our team will help you read the plans and the paperwork.
Related guides & tools
Common questions
What counts as unauthorised construction in a redevelopment project?
It is any construction that does not match the plans the municipal corporation actually sanctioned. This includes extra floors, more built-up area than the approved FSI allows, or building on set-backs and mandatory open space. Work becomes unauthorised the moment it goes beyond the approvals without a fresh, amended sanction.
Can our new building really be demolished if the builder adds extra floors?
Yes, the illegal portion can face a demolition order. Under DCPR 2034, construction in Greater Mumbai must follow the sanctioned plan, and unauthorised work can attract penalties and demolition. This is why deviations should be caught and stopped early, before the structure is complete.
What happens if our building does not get an Occupancy Certificate?
Without an OC, occupation is technically illegal and daily life becomes difficult. Banks may refuse home loans against the flats, buyers often walk away, and property tax and water charges can be levied at penal rates. Members can be left owning flats that are hard to sell, mortgage or insure.
Can the developer change the sanctioned plan on its own?
No. Section 14 of RERA, 2016 says a promoter cannot alter the sanctioned plans, layout or specifications without the written consent of at least two-thirds of the allottees. If changes are being made without that vote, your society is entitled to object and withhold consent until the process is followed properly.
How can our society check the sanctioned plans ourselves?
Ask the developer in writing for the IOD, Commencement Certificate and latest approved plans, and cross-check them on the MahaRERA portal. Appoint an independent architect or PMC to audit the site against those plans. If the developer refuses to share documents, apply under RTI to the municipal corporation for certified copies.
Who do we complain to about illegal construction?
Start with the Building Proposal department of your local ward office, addressed to the Executive Engineer, with the plot's CTS number and a clear description of the deviation. In Mumbai this is the BMC (MCGM); elsewhere it is your city's municipal corporation. Keep dated copies of every complaint and reply, and escalate if the ward office does not act.
Is unauthorised construction by a developer a criminal offence?
It can be, where there is deliberate deception. The offences of cheating under Section 318 and criminal breach of trust under Section 316 of the Bharatiya Nyaya Sanhita, 2023 may apply, and a society can file an FIR. Members can also pursue remedies through MahaRERA, the Consumer Protection Act, 2019, and the Co-operative Court.
The builder says the extra construction will be regularised later. Should we rely on that?
Treat it as a warning sign, not a reassurance. Regularisation is discretionary and is never guaranteed, so a society that relies on it can be left carrying the risk. Insist that everything is properly sanctioned before it is built, rather than accepting a promise to fix the paperwork afterwards.
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