How to Stop Spam Calls and SMS in India (DND and TRAI Guide 2026)

There are two very different things ringing your phone, and the reason most people fail to stop spam calls in India is that they treat both the same way. One is registered telemarketing, which is legal, regulated, and can be switched off with a preference setting. The other is outright fraud from a random ten-digit number, which no preference list will ever touch because the caller is already breaking the law.

Sorting your incoming nuisance into those two buckets tells you exactly which tool to use: the regulator’s Do Not Disturb system for the first, and a fraud report plus on-device screening for the second. This guide from TechLein covers DND registration through 1909 and the official app, category-wise blocking, how to report unsolicited commercial communication properly, what call screening apps really cost you in privacy, and where to report a fraud call so it goes somewhere useful.

Key takeaways

• DND blocks registered telemarketers. It has no effect on fraudsters calling from ordinary mobile numbers.
• Send START 0 to 1909 for full blocking, or pick categories if you want bank and offer messages to continue.
• Reporting a specific spam message to 1909 is what actually gets a telemarketer penalised. Ignoring it does nothing.
• Report suspected fraud calls and messages through the Chakshu facility on the government’s Sanchar Saathi portal.

Telemarketing spam versus fraud

Registered telemarketers are entities that have signed up with an operator, use an alphanumeric sender header rather than a personal number, and are bound by the regulator’s commercial communication rules. Their calls arrive from the 140 number series. Banks and service providers sending you transactional or service calls use the 1600 series. Both of these are traceable, and both are subject to your registered preferences.

Fraud is different in kind. A caller pretending to be from a courier company, a bank’s fraud desk, a telecom department officer or the police is not a telemarketer at all. They call from ordinary ten-digit numbers, or from internet numbers spoofed to look Indian. DND is irrelevant to them. If the call is designed to frighten you into a payment or a screen-share, you are looking at something closer to the digital arrest scam, and the response is a fraud report, not a preference change.

Registering for DND

1. Decide first whether you want everything blocked or only some categories. Full blocking also stops promotional messages you may actually want, such as recharge offers.
2. For full blocking, send an SMS reading START 0 to 1909 from the number you want registered.
3. For category-wise blocking, send START followed by the numbers of the categories you want to block, separated by commas, to 1909.
4. Alternatively, install the official DND app published by the telecom regulator, or use the DND section inside your operator’s own app, and set preferences through the interface.
5. Wait. Registration is acknowledged quickly but takes a few days to take full effect across telemarketer databases.
6. Check your status any time by sending STATUS to 1909. To cancel registration entirely, send STOP to 1909.
7. Repeat the process on every number you own, including the second SIM you rarely use. Preferences are per number.

Category-wise blocking

Full DND is blunt. Many people want to keep bank alerts and offers while killing property and insurance calls. The regulator maintains a numbered list of commercial categories for exactly this. The list below reflects the categories in common use; treat it as indicative and confirm the current numbering inside the official app before sending codes.

One consequence worth knowing: if you block the communication and entertainment category, you stop getting operator promotional messages about plan changes. That is not a disaster, but it means you have to check plan pages yourself. Our guide on comparing mobile recharge plans on value explains how to do that properly, which is a better basis for a decision than a promotional SMS anyway.

Reporting unsolicited commercial communication

Registering for DND is passive. Reporting is what has teeth, because repeated complaints against a sender lead to action against the telemarketer and the entity that hired them.

To report a spam SMS, forward the message exactly as received, including the sender header, to 1909. Do not retype it. To report a call, send an SMS to 1909 with the calling number and the date of the call, or use the complaint section of the official DND app, which pulls the details from your call and message logs and formats the complaint for you. The app is easier and less error-prone.

Complaints must be filed within the window the regulator allows after you receive the communication, currently a few days rather than weeks. Old messages will be rejected, so report while it is fresh. You will get an acknowledgement with a complaint reference, and a status update later.

Reading the sender header

A legitimate commercial SMS arrives from an alphanumeric header rather than a phone number. The header identifies the operator and the message type, so service, transactional, promotional and government messages are distinguishable. If a promotional message arrives from a plain ten-digit mobile number, the sender is unregistered, and that is precisely what the complaint mechanism exists to catch.

On-device call screening and what it costs

Your phone can filter a lot of this before it ever rings. The choices differ in how much data they take from you.

The built-in option

The Google Phone app that ships on most Android handsets has a caller ID and spam protection setting. Turn it on under the Phone app’s settings, in the caller ID and spam section, and enable spam filtering so suspected spam goes straight to a separate list without ringing. On Pixel devices, Call Screen goes further and can answer unknown calls with an automated assistant and show you a live transcript before you decide to pick up. Samsung handsets have an equivalent Smart Call feature. These work from a network-side reputation database and do not require uploading your address book.

Third-party caller ID apps

Apps like Truecaller identify far more numbers, because their database is built from users’ own contact lists. That is also the trade-off. The identification quality you enjoy exists because other people’s phone books were uploaded, and your number is in the database because someone you know installed it. These apps typically want call log, contacts and default-dialler permissions, which is broad access to a sensitive part of your life.

That is not an argument to never use one; it is an argument to be deliberate. If you install one, review what it can access, decline contact upload where the app offers a choice, and revoke permissions you do not need. Our guide on how to protect your privacy online covers how to audit app permissions on Android in general.

Silencing unknown callers

The simplest option costs nothing and leaks nothing: turn on the setting that silences calls from numbers not in your contacts. They still appear in your call log and can leave voicemail, but the phone does not ring. If your work involves calls from strangers this is unusable; if it does not, it is remarkably effective.

Reporting fraud, not just spam

For a call or message you believe is a scam attempt rather than marketing, the right destination is the Chakshu facility on the Department of Telecommunications’ Sanchar Saathi portal. You submit the number, the medium, a category such as fraudulent bank or KYC call, the date and time, and a short description with a screenshot if you have one. Reports feed into the system that gets fraudulent connections disconnected.

If money has already moved, that is a different and more urgent matter. Report it immediately through the national cybercrime reporting portal or the cyber financial fraud helpline on 1930, because the chance of freezing a transfer falls sharply with time. Our guide to UPI payment fraud protection covers what to do in the first hour.

One specific scam worth naming: callers who ask for a code sent to your phone, whether an OTP or a porting code. Nobody legitimate needs either over the phone. If you are genuinely in the middle of porting your mobile number, the code is handed over in person at the new operator’s counter and never to a caller.

What DND cannot do

It cannot stop calls from unregistered senders using ordinary SIM cards, though reporting them helps get those connections cut. It cannot stop international or internet-originated calls spoofed to look like Indian numbers. It does not apply to messages from your own operator about your account, or to genuinely transactional messages such as OTPs and payment alerts, which you would not want blocked anyway. And it takes a few days to bite, so judge it after a week rather than the next morning.

Managing spam is also easier if your handset is set up sensibly to begin with. The habits in our guide on how to manage your connections and eSIM profiles apply here too: know which numbers are active in your name, and retire the ones you no longer use, because a dormant SIM you never check is a magnet for junk.

Frequently asked questions

How long does DND take to work?

The registration is recorded quickly, but telemarketer databases refresh over a few days. Give it about a week before judging whether it worked.

Will DND block my bank OTPs?

No. Transactional and service messages such as OTPs, payment alerts and delivery updates are not commercial promotions and continue regardless of your preferences.

I registered for DND but calls continue. Why?

Almost always because the callers are unregistered, using ordinary mobile numbers. File complaints against those specific numbers through 1909 or the official app so they can be acted on.

Is Truecaller safe to use?

It is widely used and does what it claims, but its database is built from uploaded contact lists and it asks for broad permissions. Weigh that against the built-in spam filter, which is less comprehensive but far less invasive.

Where do I report a scam call rather than a marketing call?

Use the Chakshu facility on the Sanchar Saathi portal. If money has been lost, report through the national cybercrime portal or the 1930 helpline immediately.

The bottom line

Spend twenty minutes once and the difference is permanent. Register your numbers for DND with the categories you actually want blocked, turn on the built-in spam filter in your phone app, and decide consciously whether a third-party caller ID app is worth the access it wants.

After that, the only ongoing habit that matters is reporting. A spam SMS forwarded to 1909, or a suspicious call submitted through Chakshu, takes under a minute and is the only part of the system that produces consequences for the sender. Silence and irritation produce none.