How to Stop Spam Calls and SMS in India: The Full DND Guide (2026)

Send START 0 as an SMS to 1909 from the number you want cleaned up. That one message registers your phone under TRAI's Do Not Disturb list in the "fully blocked" category, and every registered telemarketer in India is then barred from calling or texting it. It works the same on Jio, Airtel, Vi and BSNL, it is free, and it takes about ten seconds.

That is the whole answer for most people. The rest of this guide is for the part nobody tells you: DND stops registered telemarketers, and a large share of the junk hitting Indian phones in 2026 is not coming from registered telemarketers at all. Those need a different lever, and there is one.

What DND actually is

DND runs under TRAI's TCCCPR 2018 rules. Every company that wants to send commercial calls or SMS in India has to register as a telemarketer, use a recognised sender header, and check the DND database before it dials. Register your number and you drop out of their permitted list. Ignore it and they face penalties from their own telecom operator.

The practical effect: loan offers, credit card pitches, real-estate cold calls, insurance renewals, coaching-class blasts and "congratulations you have won" SMS from legitimate-but-annoying businesses stop arriving.

The three ways to register

By SMS (fastest). Text START 0 to 1909. Zero is the code for a full block — nothing commercial at all. You get a confirmation SMS back.

By call. Dial 1909. It is toll-free. An IVR walks you through the same options. Useful on a feature phone, or when setting this up for a parent.

By app. TRAI publishes the DND 3.0 app for Android and iOS. It handles registration, lets you pick categories instead of a blanket block, and — the reason to install it — it can read your call and SMS log so you can file a complaint straight from the offending entry instead of retyping the number.

Whichever route you take, give it a full day before judging the result. The preference has to propagate to every registered telemarketer's system, so the first few hours after registering are not a fair test.

Block everything, or only some of it?

A full block is the right default, but there are seven categories you can allow selectively if you want some commercial messages through:

Category	Typical sender
Banking, insurance, financial products, credit cards	Bank offers, policy renewals
Real estate	Builder launches, broker calls
Education	Coaching, admissions, test prep
Health	Diagnostic labs, clinics, pharmacy
Consumer goods and automobiles	Retail sales, car dealers
Communication, broadcasting, entertainment, IT	OTT, DTH, telecom plans
Tourism and leisure	Holiday packages, timeshares

Pick these in the DND 3.0 app or from the 1909 IVR. Most people who start with categories end up on a full block within a month anyway.

To undo the registration entirely, SMS STOP to 1909.

The part DND does not fix

DND is a leash on registered businesses. It does nothing about:

• Fraud and scam calls placed from ordinary 10-digit SIMs — fake courier calls, "your KYC is expiring", digital-arrest scripts, fake job offers.
• WhatsApp and Telegram spam, which is not telecom commercial traffic at all.
• Unregistered telemarketers using ordinary SIM cards precisely to stay outside the system.

For those, the tool is Sanchar Saathi (sancharsaathi.gov.in), the Department of Telecommunications portal. Two parts of it matter:

• Chakshu — report a suspected fraud call, SMS or WhatsApp message. You submit the number, the medium, the date and a screenshot or short description. Reports feed the disconnection pipeline.
• TAFCOP — shows every mobile connection issued against your ID. If a SIM you never bought is on that list, flag it there. Worth doing once even if you have no spam problem at all.

How to tell a real call from a fake one

Two number ranges make this easy in 2026:

• 140-series — registered telemarketing. Sales calls are supposed to originate here. A sales pitch from a plain 10-digit mobile number is already off-script.
• 1600-series — transactional and service calls from banks and financial institutions. Your bank calling about a genuine transaction should show a 1600 number.

So: a "bank" calling from a regular mobile number and asking for an OTP is not your bank. No exceptions. Banks do not ask for OTPs, and no legitimate caller needs remote access to your phone.

For SMS, registered senders use a six-character alphanumeric header, not a mobile number. A promotional SMS arriving from a personal-looking 10-digit number is unregistered by definition.

Complaining when somebody ignores your DND

Registering is step one; the rule only bites if violations get reported.

Send the complaint to 1909, or file it in the DND 3.0 app, in this shape: the offending number or SMS header, the date, and the content of the message. Do it the same day — the complaint window is short, and a screenshot from last month is no use.

You get a complaint reference in return. The telemarketer's own operator has to act on it, and repeat offenders lose their registration and their deposit. This is the only part of the system with teeth, and it is the part almost nobody uses.

Handset-level filtering, in two minutes

Do this whether or not you register, because it catches the unregistered callers DND cannot touch.

Android: open the Phone app, go to Settings, and switch on Caller ID & spam. Google flags suspected spam and can silence it outright. The same Settings screen has Blocked numbers, where you can block unknown and private callers as a class.

iPhone: Settings, then Phone, then Silence Unknown Callers. Anyone not in your contacts, recent outgoing calls or Siri suggestions goes straight to voicemail and still shows up in Recents. Also turn on Filter Unknown Senders under Settings, Messages, to push SMS from strangers into a separate tab.

Both: report a spam SMS from inside the messaging app instead of only deleting it. That feedback trains the filter for everyone.

A realistic sequence

1. SMS START 0 to 1909. Repeat on every SIM in the house, including the one in a mobile hotspot or a tablet.
2. Install DND 3.0 and register the same numbers there, so complaining later takes one tap.
3. Turn on handset spam filtering on every phone.
4. Check TAFCOP once for SIMs issued in your name.
5. For the next month, report every violator the same day. Volume drops fastest for the people who complain.

Numbers that sit in a drawer count too — a data-only SIM in a router or dongle collects marketing SMS like any other connection, and nobody is watching that inbox. If you are setting one up, our portable 4G/5G WiFi dongle deal is live right now, and the rest of the day's price-verified electronics sit on /offers.