Building Height Clearance / Building AAI NOC

If you’re putting up a building anywhere near an airport in India, chances are someone at the site office has already asked you whether the AAI NOC is in place. Building height clearance from the Airports Authority of India is one of those approvals people tend to leave for later — right until the municipal body refuses to sanction the building plan without it. This page walks you through what building height clearance actually means, when you need an AAI NOC, how the process works, and what it takes to get it approved without your project losing weeks in back-and-forth.

What Is Building Height Clearance (AAI NOC)?

Building height clearance is the approval AAI gives confirming that the height of your proposed structure will not interfere with aircraft operations, radar, or navigation aids at a nearby airport. In practice, this comes as a No Objection Certificate — commonly called the AAI NOC — issued after your site coordinates and elevation are checked against the airport’s obstacle limitation surface and the Colour Coded Zone Map for that region.

Every airport in the country, civil or defence, has a protected zone around it. Inside that zone, the maximum height you’re allowed to build depends entirely on how far your plot sits from the airport reference point and what the terrain elevation is at your exact location. That’s why this approval isn’t a generic paper — it’s tied to your specific coordinates.

When Do You Actually Need an AAI NOC for Height Clearance?

Not every building attracts this requirement, but a fair number do, especially in cities that have grown around their airports over the years. You’ll typically need a building AAI NOC if:

• Your plot falls within roughly 20 km (or the notified radius) of an airport reference point
• You’re constructing a multi-storey residential or commercial building beyond the permitted local height
• You’re putting up a telecom tower, transmission line, or broadcast mast
• You’re building an industrial structure with a chimney, silo, or tall equipment
• You’re installing wind turbines or a solar plant with elevated components
• You need a temporary crane or tower crane that will exceed the local height limit during construction

If your plot lies outside the regulated distance and your building stays under the general height limit, you may not need to apply at all — the AAI’s own colour-coded zoning system settles a large share of applications automatically. The only way to know for sure is to check your coordinates against the zone map, which is exactly where a proper site survey comes in.

How the AAI NOC / Height Clearance Process Works

The process runs through AAI’s online system, NOCAS (No Objection Certificate Application System). It’s fairly mechanical once your survey data is ready, but each step depends on the one before it.

1. Site survey: A licensed surveyor records your site’s exact coordinates (WGS-84 datum) and ground elevation (AMSL) using DGPS or Total Station equipment.
2. Zone check: These coordinates are checked against the Colour Coded Zone Map to find the maximum permissible height at your exact plot.
3. Document preparation: A site elevation certificate, coordinate certificate, layout plan, and ownership proof are compiled in the format NOCAS accepts.
4. Online application: The case is filed through the NOCAS portal, along with scanned copies of every supporting document.
5. Remarks and clarification: If AAI raises a query — which happens often when coordinates or documents don’t match — someone needs to respond quickly, or the file sits pending.
6. Issuance: Once cleared, you get the certificate, valid for a fixed number of years depending on the structure type.

Documents Needed for a Building AAI NOC

Colour Coded Zone Map and Permissible Height

The Colour Coded Zone Map is what actually decides your permissible building height, not a fixed rule of thumb. Zones are graded from green through yellow to red, with red areas closest to the flight path carrying the tightest restrictions. Two plots a few hundred metres apart can have very different height caps depending on the terrain and their position relative to the runway centre line. This is also the part applicants get wrong most often — assuming their allowed height based on a neighbouring building instead of their own surveyed coordinates.

How Long Does an AAI Height Clearance NOC Take?

The field survey for coordinates and elevation is usually wrapped up within a few days. Getting the certified documentation ready typically takes another two to four weeks. AAI’s own processing time on NOCAS varies by case load and airport, so it’s worth applying early rather than waiting until your building plan is stuck at the municipal approval stage.

Validity of the Building Height Clearance NOC

Once granted, this NOC is generally valid for up to 8 years for buildings, and up to 12 years for masts and chimneys. If construction is still underway when it expires, it can be revalidated through NOCAS rather than filed as a fresh application.

Why Get Your Survey Done by Surveying India

We’ve handled this survey work for developers, telecom companies, and industrial projects across multiple airport zones in India, so we know how AAI reviewers actually check applications — not just what the checklist says. A few things that make a real difference in getting your application approved on the first attempt:

• In-house DGPS and Total Station survey teams, so coordinate and elevation data comes from the same crew, cutting down transcription errors between field and paperwork
• DGCA-recognised drone operators for sites where aerial data adds clarity, with the necessary flight clearances handled as part of the job
• Direct experience with NOCAS submissions, including how to respond to remarks without losing weeks on avoidable resubmissions
• Over a decade of survey work delivered for government bodies, PSUs, and private developers across India

Frequently Asked Questions

Regulatory reference: applications and the current Colour Coded Zone Map are maintained by the Airports Authority of India on the official AAI NOCAS portal. Always verify the latest permissible height for your coordinates there before finalising your building design.