How to Invoke an Arbitration Clause: Notice Under Section 21

What is an arbitration notice under Section 21?

Section 21 of the Arbitration and Conciliation Act, 1996 says that, unless the parties have agreed otherwise, arbitral proceedings for a particular dispute begin on the date the respondent receives a request for that dispute to be referred to arbitration. Lawyers call that request the Section 21 notice, or the notice invoking arbitration. It's a short document. It does three jobs at once.

It fixes the date the arbitration starts, and that's the date that counts for limitation. It tells the other side exactly which claims are being referred, so they can answer or settle. And it starts the 30-day clock in Section 11 for agreeing on or appointing an arbitrator. When that clock runs out, the High Court can step in.

Don't mix it up with an ordinary legal notice demanding payment. A demand notice threatens action. A Section 21 notice is the action. Many disputes need both, a demand first and the invocation later. One letter can do both jobs, but only if it plainly asks for the dispute to be referred to arbitration. We see a lot of letters that don't.

Why the date they receive it matters more than the date you send it

The Act ties the start of the arbitration to receipt, not dispatch. Section 43(2) then treats the arbitration as having started on that same date for the Limitation Act, 1963. Say your oldest invoice fell due on 15 November 2023. The three-year period for that claim generally ends on 15 November 2026, and the notice has to reach the other side before then. Putting it in the post on the last day won't do.

Section 3 of the Act explains when a written communication counts as received. That's when it's handed to the addressee personally, or delivered at their place of business, habitual residence or mailing address. If none of those can be found after reasonable inquiry, a letter sent to the last known address by registered post, or by any other method that records the attempt to deliver, is deemed received. Courts are strict about this. In Indian Spinal Injuries Centre v. Galaxy India (2024), the Delhi High Court threw out a Section 11 petition because the notice had gone to an incomplete address. Issuing a notice, it held, isn't the same as serving it.

Before a word of the notice is written, Advocate B.K. Singh checks two dates: when the oldest claim runs out, and when the notice is likely to be delivered. If they're close, we don't trust the post alone. The notice goes by hand against an acknowledgment and by email the same day. Registered post follows as a backup.

The provisions behind a notice invoking arbitration

Do you have to finish the pre-arbitration steps in the clause first?

Lots of contracts, construction, infrastructure and government ones in particular, lay down steps before arbitration. A meeting between senior officers. A reference to the engineer-in-charge. A dispute resolution committee, or mediation, each with its own time limit. Courts haven't treated all these steps the same way. It turns on the wording, on whether the step is framed as a condition, and on whether following it would be pointless because the other side has already refused to talk.

Our advice is to do the steps anyway, and leave a paper trail. Keep the letter in which you asked for the meeting. Keep the minutes, or proof that they never replied. Note the date the period ended, and refer to all of it in the notice. Now and then limitation is close while the pre-arbitration period still has weeks to go. In that case the usual practice is to send the notice regardless, recording that the meeting has been requested and that you're invoking arbitration so your claims don't become time-barred. A tribunal can sort out a procedural objection. A claim that's dead on limitation, it can't revive.

Also, pre-institution mediation under Section 12A of the Commercial Courts Act, 2015 is for commercial suits, not arbitration. You don't need to go through it before sending a Section 21 notice.

What a notice invoking arbitration has to contain

• The right parties. Give the full legal name of the claimant and of every respondent, exactly as in the contract and the Registrar of Companies or GST records, with registered office and correspondence addresses. Use only a trade name and you'll pay for it later.
• The contract and the clause. Identify the agreement by its date and reference number, and quote the arbitration clause word for word, seat, institution and appointment wording included.
• The dispute, plainly told. A short account of what went wrong. Goods supplied, work done, payments missed, the termination, the defects they're alleging. Two or three paragraphs usually cover it.
• The claims. Each head of claim with a figure wherever you can give one: principal, interest (with the rate and why you're entitled to it), damages, return of security, costs. Add a line reserving your right to amend and add claims.
• The request. One clear sentence saying you're invoking arbitration under the clause and Section 21, and asking for the disputes set out to be referred to arbitration. Don't leave it to inference.
• The arbitrator. Depending on the clause, either the names you propose for a sole arbitrator with a request that they agree, or your nominee's name with a request that they name theirs.
• Time to respond. Thirty days from receipt, in line with Section 11, and a statement that you'll go to court if they don't respond.
• Signature and authority. Signed by an authorised officer, or by an advocate on instructions with the authority on record. You can attach or list the main documents if it helps.

Notice invoking arbitration format: how the letter is laid out

The law doesn't prescribe any form. A notice invoking arbitration format that works is a plain one. Head the letter with how it's being sent (by hand, speed post, registered post with acknowledgment, email), the date, and each addressee's name and address. Use a subject line along the lines of 'Notice invoking arbitration under Clause 18 of the Supply Agreement dated 4 April 2022 read with Section 21 of the Arbitration and Conciliation Act, 1996'. Nobody reading that can later claim they didn't know what it was.

Inside, use numbered paragraphs and keep them in a sensible order. Start with the parties. Then the contract and the terms that matter, what you supplied or built, and where the other side fell short. Mention the earlier letters, including any demand notice and their reply. After that come the claims with amounts, the clause in full, the actual invocation, your suggestion on the arbitrator, the 30-day request and a line reserving your rights. A claims table at the very end reads much better than numbers scattered through the text.

Keep it calm. The arbitrator will read this notice later, and so might a judge at a Section 11 hearing. Accusations of cheating or threats of a police complaint add nothing, and they make settlement harder. We don't publish a downloadable template, because the right format depends on the clause. Ask us for the current format if you want yours checked against your contract.

Naming the arbitrator in the notice without spoiling the appointment

If the clause says the parties will agree on a sole arbitrator, propose two or three names, each someone with no connection to either side. Ask the other side to agree to one, or suggest alternatives, within 30 days. Don't appoint someone yourself and announce it. A one-sided appointment is open to challenge, and it can bring the award down years later.

With three arbitrators, name your nominee. Confirm that your nominee has been asked to make the Section 12 disclosure. Then call on the other side to name theirs within 30 days. If they don't, Section 11(4) lets the High Court appoint for them.

Sometimes the clause hands the appointment to their managing director, their chief engineer or some other officer, or simply names one of their employees as arbitrator. Say clearly in your notice that a clause like that can't work any more, citing Perkins Eastman v. HSCC (2019) and the Constitution Bench ruling in Central Organisation for Railway Electrification v. ECI-SPIC-SMO-MCML (2024). Then offer independent names. If they still insist on their own pick, that refusal is what you take to the High Court in a Section 11 petition. Our guide on why a one-sided arbitrator appointment is invalid walks through the case law.

Where the clause names an institution, such as the Delhi International Arbitration Centre, its rules usually say how the arbitration starts. Often that's by filing a Request for Arbitration with the Centre. Send the notice to the other side too, but follow the institution's filing steps. Our sister site explains how a DIAC arbitration is started.

How should the notice be sent, and to whom?

Start with the notices clause in the contract. Most commercial contracts say where notices go and how, sometimes naming a person by designation and giving an email address. Follow it to the letter. Then add other methods to be safe. For a company, also send it to the registered office shown on the Ministry of Corporate Affairs portal (check it on the day you send), and to whichever site or branch office you actually dealt with.

Don't rely on one channel. Use speed post or registered post with tracking, a courier company with a name, hand delivery with a rubber-stamped acknowledgment, and email to the addresses both sides used while the work was on. Print the page showing 'delivered'. File the postal receipts. Save the email with full headers, and any auto-reply. Was WhatsApp how you normally dealt with them? Then a copy there won't hurt. It just can't be the only way you sent it.

We sometimes get a file only after a Section 11 petition has hit trouble in the High Court. Usually the problem isn't the wording of the notice. It's proof that the notice arrived. If the letter went to an old or wrong office, with no tracking printout and no email, the hearing turns into a fight about service and the arbitrator question waits. That's why Advocate B.K. Singh keeps a single-page service record for each notice, showing every mode, every date and every proof, and files it along with the petition.

Serve everyone you plan to proceed against. In Adavya Projects v. Vishal Structurals (2025), the Supreme Court held that a party who wasn't served with the Section 21 notice can still be joined in the arbitration if it's a party to the arbitration agreement. Serving everyone at the start avoids that fight altogether. For group companies and others who never signed, see when someone who didn't sign can still be bound by an arbitration clause.

How to invoke an arbitration clause, one step at a time

1. Read the arbitration clause and the notices clause

   Note the seat, any institution, the number of arbitrators, how they're appointed, any pre-arbitration steps and where notices must go. And check the clause actually covers your dispute. Sometimes it doesn't.

2. Work out the limitation dates

   List every claim with the date it arose, plus any part payment and any written acknowledgment, because Sections 18 and 19 of the Limitation Act restart the period. Mark the earliest date by which the notice has to be received.

3. Finish or record the pre-arbitration steps

   Write asking for the meeting or mediation the clause requires. Short on time? Put the request on record and move on to the notice.

4. Check names and addresses

   Confirm the exact legal names and registered offices on the MCA portal or GST records. Decide which group companies, if any, should get the notice as well.

5. Draft the notice

   Set out the facts, the claims with figures, the clause, the invocation, your proposal on the arbitrator and the 30-day request. Get someone to tick the claim figures against the ledger.

6. Line up arbitrator names

   Before proposing anyone, ask around informally about availability and conflicts. Tell your nominee to be ready to make the Section 12 disclosure.

7. Send it several ways and keep the proof

   Send by hand, speed post or registered post, courier and email, all on the same day. Gather the acknowledgments, tracking reports and email records into one service file.

8. Diarise day 30 and plan what comes next

   Count 30 days from the date of receipt. No agreement by then? Prepare the Section 11 petition, or the Request for Arbitration if an institution is named.

What happens once the other side gets the notice?

Usually one of four things. They agree to one of your proposed arbitrators and the arbitration gets going. They propose their own names, and a short back and forth follows until someone's agreed. They write back denying the claims and disputing whether there's an arbitration agreement at all, or what it covers. Or they say nothing.

Most often? Nothing at all. That's fine for you. When 30 days from receipt pass without an agreed name, the Section 11 route to the High Court opens. One wrinkle comes from the Supreme Court in Datar Switchgear v. Tata Finance (2000). The other side keeps its right to appoint even after those 30 days, right up until you file your Section 11 petition. Once you file, that right is gone. So don't sit on it after the period ends. Our guide on when you can go to court under Section 11 for an arbitrator picks up from there.

If the relationship has really broken down, expect a counterclaim. They may send their own notice listing claims against you, damages for delay or defects, say. That doesn't change where you stand. Your lawyer should still read it, for limitation and for anything that needs a quick answer.

When is it too late to send a Section 21 notice?

Most money claims carry a three-year limitation period under the Limitation Act. Article 14 covers the price of goods sold and delivered, Article 18 the price of work done, and Article 55 breach of contract. For each claim, the arbitration must start within that period, which means the notice must be received within it. A written acknowledgment of the debt signed by the other side (Section 18), or a part payment (Section 19), starts a fresh period from that date. So go through the ledgers, balance confirmations and emails with care.

And then a second clock starts. Once the other side has had the notice for 30 days and no arbitrator has been appointed, you have a limited time to go to the High Court. In BSNL v. Nortel Networks (2021), repeated in Arif Azim v. Aptech (2024), the Supreme Court fixed that at three years under Article 137 of the Limitation Act, counting from the day the other side failed to act on your notice. A fresh notice on the same claims won't reset it. Courts have refused that. People do try.

If a claim is already past three years and nothing restarted the clock, a notice won't revive it. The detailed rules are in when limitation applies to arbitration claims and our sister site's guide on limitation for recovering money.

Time and costs from notice to tribunal

Papers to gather before anyone drafts the notice

Where the notice leads: which court or institution takes over

Agree on a name and no court is involved at this stage. You go straight to the tribunal. No agreement? Then the seat decides where the Section 11 petition is filed. For a domestic arbitration it's the High Court that covers the seat: the Delhi High Court if the seat is New Delhi, the Allahabad High Court for Noida or Ghaziabad, the Punjab and Haryana High Court for Gurugram or Faridabad. International commercial arbitrations are different. Their Section 11 petitions are filed in the Supreme Court.

In practice the Delhi High Court tends to appoint a sole arbitrator and send the matter to the Delhi International Arbitration Centre, to be run under its rules. Need urgent protection while you wait for the appointment? File a Section 9 petition in the court that has jurisdiction, which in Delhi turns on the value of the dispute. Our guide on where to file a Section 9 petition for urgent interim relief explains the choice.

There's one exception you shouldn't skip past. Suppose your business is a registered micro or small enterprise under the MSMED Act and the fight is over late payment for goods or services you supplied. You may be able to go to the MSME Facilitation Council under Section 18 instead, and the Supreme Court has said that route beats a private arbitration clause. Parts of the Council's procedure are being changed by the MSMED (Amendment) Act, 2026, which hadn't been fully notified as of late October 2026. Check where things stand. And read how the MSME Facilitation Council works before any Section 21 notice goes out.

Mistakes that make a Section 21 notice useless

• Sending it to the wrong entity. You address it to a sister company, a brand name or the proprietor, not the company that signed. Expect the objection that the arbitration never started against the right party.
• Leaving claims out. The arbitration starts only for the disputes in the notice. Add a claim years later and the other side will argue it's time-barred, even though the arbitration itself began earlier.
• A demand notice that never asks for arbitration. A letter that only demands payment and threatens a suit doesn't invoke arbitration. However strongly it's worded.
• Appointing your own sole arbitrator. It feels quick. It can make the whole proceeding void and the award unenforceable.
• No proof it was delivered. Without tracking reports or acknowledgments you're left arguing about receipt, and nobody can say for sure when the arbitration began.
• Skipping a pre-arbitration step and saying nothing about it. Even if the step isn't mandatory, your silence hands the other side an easy objection.
• Sending it too late. A notice received after a claim's limitation date doesn't save that claim. Look at the oldest invoices first.
• Lifting a clause from another contract. Templates often quote the wrong clause number or the wrong seat, and that confuses the court hearing the Section 11 petition. Our list of mistakes people make in arbitration clauses shows how small wording slips turn into big problems.

If you've received a notice invoking arbitration

First, note the date it reached you, because your 30 days count from that day and nobody will extend them for you. Then read the clause they're relying on. Do their claims fall inside it? Have they named the right parties, or written to a sister concern that never signed anything? Does any claim look past limitation? Reply inside the 30 days. You can accept one of their names, offer your own, or put your objections on record. Even if you think the whole claim is rubbish, it's usually smarter to have a say in who the arbitrator is than to keep quiet and let the court pick.

Objections on limitation, on the merits, or on whether a claim falls within the clause are mostly for the tribunal to decide later under Section 16. They aren't reasons to refuse to take part. Got claims of your own? Prepare them now. For a counterclaim, limitation generally stops when the claimant receives your notice raising it. If you never send one, it stops only when you file the counterclaim before the tribunal. So if your claims are getting old, send your own notice early.

What to do this week

Get the contract out and find two clauses, the arbitration clause and the one about notices. Write down each claim next to the date it fell due. Hunt for anything that resets the clock, like a signed balance confirmation or a part payment. Then look up the other side's registered office on the MCA portal, because companies move and rarely tell their suppliers. Is any claim a few months away from turning three years old? Then the notice is urgent, and one more round of phone calls won't help. Our arbitration lawyer page explains how we handle these matters from notice to award.

If you'd like the clause, the dates and your draft notice checked before it goes out, send your papers to Advocate B.K. Singh's team through the contact page.