What Do Not Disturb Actually Blocks on Your Number

DND — Do Not Disturb — is the one setting every Indian mobile user should know about. It tells your operator to block promotional calls and SMS from reaching you, and TRAI's rules back it. This guide explains what DND does, how to set it up, and what to do when messages still slip through.

What DND actually is

DND is a consumer service under the rules of the Telecom Regulatory Authority of India (TRAI), run by every Indian mobile operator. When you register a preference, it is recorded in the National Customer Preference Register (NCPR), which TRAI's rules call the Preference Register. A promotional message can reach you only if you have not blocked promotions in its category, or if you have given the sender your explicit digital consent.

Think of it as a "block list for marketing"that works at the network level. You don't have to install an app, and you don't have to block individual numbers. You register your preference once, and compliant senders cannot deliver promotional messages against it.

What DND blocks and doesn't block

DND is specifically scoped to promotionalcommunication. It does not block the messages you actually need. Under TRAI's rules, transactional messages, service messages and government communication still reach you, because TRAI treats them as important to customers.

One more rule: if a business sends a service message on your explicit consent, TRAI's 2026 amendment treats it as a promotional message based on explicit consent. You can withdraw consent through the mechanism your operator provides.

Why DND exists

Unwanted commercial calls and SMS became a public nuisance, and TRAI stepped in. Its first regulations, notified in 2007, set up a National Do Not Call Registry. New regulations followed in 2010, and its TCCCPR 2018 regulations rebuilt the system on a shared ledger, with every sender and message template registered through DLT.

TRAI has kept tightening the rules, most recently with amendments in February 2025 and September 2026. A sender found to be sending unsolicited commercial messages can have all outgoing services barred for 15 days on a first violation. A second violation can mean disconnection of all its telecom resources for one year and blacklisting.

How to activate DND on your number

Your operator must give you these ways to register, change or cancel a preference, free of cost and 24 hours a day. It must acknowledge your request within 15 minutes with a reference number, and TRAI's rules require your preference to be in effect, with no promotional message delivered against it, within 24 hours.

The codes are the same on every route.

Option 1: Send an SMS to 1909

From the phone you want to protect, send the text from the table to 1909. For example, send BLOCK PROMO to stop all promotional messages.

Option 2: Call 1909

Call 1909. An automated menu asks you to press the number from the table. This is the most accessible option if you're helping an older relative register a preference.

Option 3: Dial the USSD code

Dial the USSD code from the table, for example *1909*50#. It works on feature phones too, because it needs no data connection.

Option 4: An app, the web portal or customer care

TRAI's rules also allow a mobile app approved by TRAI and a web portal that checks your identity with an OTP. Your operator's own app may offer DND controls too, and you can ask its customer care to register your preference.

Still getting promotional SMS? Here's what to do

DND isn't perfect. Some senders ignore the rules, and a small number use ordinary 10-digit numbers that sit outside the registered system. If you're still receiving promotional messages, work through these four steps.

Step 1: Check your DND status

Look for the confirmation your operator sent when you registered. If you can't find it, send BLOCK PROMO to 1909 again, or ask customer care to confirm your preference. A category block stops only the categories you chose.

Step 2: Identify the sender

Transactional and service messages (OTPs, payment confirmations, delivery updates, bank alerts) and government messages aren't blocked by DND, and they will keep coming. Promotional messages are offers, discounts and launches. A business that holds your explicit digital consent can also send promotions while DND is on, so check whether you agreed to receive them.

Step 3: Report to 1909

If you registered a preference and a sender breaks it, complain within 7 days of receiving the message. You can send an SMS to 1909, call it, use an approved app, or use the operator's web portal. TRAI's rules treat a complaint as valid when it gives the sender's number or header, your own mobile number, the date of the message and a short description. Your operator must acknowledge it within 15 minutes with a reference number.

Step 4: Escalate to TRAI

Operators must investigate complaints against registered senders. If you're not satisfied with how yours is handled, you can raise it with TRAI through its website, trai.gov.in.

Limitations and edge cases

Three things DND can't fix:

1. Unregistered senders on ordinary numbers.TRAI notes that some spammers use normal 10-digit mobile or landline numbers to pass as ordinary subscribers and avoid the rules. Block and report these numbers individually, and use your phone's spam filter. If the messages arrive in a constant flood from one source, it may be SMS bombing rather than marketing, and our guide to SMS bombers in India explains the law and what to do.
2. Messages you agreed to. If you gave a business explicit digital consent, it can message you even while DND is on. You can withdraw consent through the mechanism your operator provides.
3. Automated promotional calls.TRAI directs promotional robo-calls to 140-series numbers, and you can block those through your preferences, but not every automated call is caught. Your phone's built-in spam filter adds a second layer.

Frequently asked questions