You registered for DND years ago and the calls never stopped. That is not a failure of the system so much as a misunderstanding of what it was ever designed to do — and once you know the difference, you can aim your complaints where they actually land.
What DND Is, Precisely
Do Not Disturb is a preference registry, not a firewall. It records that you do not wish to receive commercial communication, and it is legally binding on registered telemarketers — companies that have signed up with TRAI, use recognised sender headers, and can be penalised for violations.
It has no effect on unregistered telemarketers: the property broker, loan agent or crypto tout calling from an ordinary ten-digit SIM. What they are doing is illegal, but DND does not stop it, because their SIM is not part of the registered system at all.
That single distinction explains almost every complaint about DND not working. The calls you still get are, overwhelmingly, from the unregistered side.
How to Register
Any of these:
- SMS
START 0to 1909 for full DND across all categories - Dial 1909 and follow the IVR
- Use the TRAI DND app, relaunched in a revamped version on 13 February 2026
- Use your operator’s app or website
You get a confirmation SMS with a reference number straight away. The preference activates within 24 hours, and you can change it again after 24 hours have passed.
Partial DND: Keep What You Want
Full DND blocks all commercial categories. If you would rather keep some, you can block selectively across seven categories:
- Banking, insurance and financial products
- Real estate
- Education
- Health
- Consumer goods and automobiles
- Communication, broadcasting, entertainment and IT
- Tourism and leisure
Send START followed by the category numbers you want blocked to 1909. Most people are better served by full DND and re-enabling anything they miss.
Reading Sender Headers
Indian SMS headers carry a suffix that tells you the message type, and the number ranges are meaningful too:
- -P promotional, -S service, -T transactional, -G government
- 140-series numbers are for promotional robocalls
- 1600-series numbers are for service and transactional calls, including from banks
The 1600 series is worth remembering. It was introduced so genuine bank calls could be distinguished from impersonators. A call claiming to be your bank from an ordinary mobile number deserves suspicion — a useful reflex alongside knowing how the digital arrest scam works.
Complaining, and Why It Now Bites Harder
A complaint against a registered telemarketer has real consequences, and the rules were tightened by the TCCCPR amendment of 12 February 2025.
How to complain: send an SMS to 1909 in the format
UCC, <calling number or SMS header>, dd/mm/yy
You can also complain through the TRAI DND app or your operator’s app.
What changed in 2025, in your favour:
- The complaint window extended from three days to seven days after the call or message. Most sites still say three — that is outdated.
- The action trigger against unregistered telemarketers tightened to five complaints in ten days, from ten complaints in seven.
- A first violation now brings a 15-day bar on outgoing services across all operators; repeat violations can mean disconnection and blacklisting for a year.
- Operators face financial disincentives of up to ₹10 lakh per instance, capped at ₹50 lakh per licensed service area per month.
The five-in-ten-days threshold is why individual complaints matter more than they used to. Five people reporting the same nuisance number within ten days is now enough to act on it.
Why Some Messages Keep Arriving Legitimately
Two categories are exempt and always will be.
Transactional and service messages from organisations you have a relationship with — OTPs, delivery updates, bill reminders, statement alerts. DND does not and should not touch these.
Messages you consented to, often without noticing, by ticking a box while buying something. Consent requests come through the 127-series shortcode. Consent for service communication has a defined validity, and once you revoke it there is a 90-day period before that entity can seek your opt-in again.
If a company keeps messaging you after revocation, that is a genuine violation and worth a complaint.
Escalating When Nothing Happens
- Complain to your operator first, with the number, date and reference. They have seven days to act.
- If unresolved, escalate through the operator’s appellate authority.
- Report persistent unregistered callers through Chakshu on Sanchar Saathi, which handles unsolicited commercial communication as well as fraud — see our Sanchar Saathi guide.
The TRAI DND app handled over 17 lakh complaints in 2025, so the channel is being used at scale.
The Realistic Combination
DND handles the registered side. Your operator’s network filtering and your phone’s own spam controls handle much of the rest — set those up using our guide to blocking spam calls on Jio, Airtel and Vi.
Together they get you most of the way. What remains is a residue of unregistered callers that no system fully eliminates, and complaining about those is what eventually gets their connections barred. We cover Indian telecom rules in plain language at Techleez.
Frequently Asked Questions
How do I activate DND in India?
Send START 0 to 1909 for full DND, or dial 1909. You can also use the TRAI DND app or your operator’s app. It activates within 24 hours.
Why do I still get calls after registering for DND?
DND binds registered telemarketers only. Calls from unregistered telemarketers using ordinary SIM cards are illegal but are not blocked by the registry.
How many days do I have to complain about a spam call?
Seven days, extended from three by the February 2025 amendment. Many sites still quote the old three-day window.
What is the SMS format for a DND complaint?
Send UCC, followed by the calling number or SMS header, followed by the date in dd/mm/yy format, to 1909.
What are 140 and 1600 numbers?
140-series numbers are used for promotional calls. 1600-series numbers are reserved for service and transactional calls, including genuine bank communication.
Will DND stop my bank OTPs?
No. Transactional and service messages from organisations you have a relationship with are exempt and continue to arrive.
Fold Smith
Fold Smith is a technology journalist and the lead editor of The Techleez, an India-first publication that decodes technology, digital payments, streaming and online culture for everyday readers. From UPI and fintech explainers to OTT streaming guides, Android tips and online-safety checklists, he personally tests the apps, tools and services featured on the site before recommending them. His focus is practical, research-backed guidance that helps Indian readers make smarter digital decisions — spend less, stream better and stay safe online. When he is not writing, he is usually tracking NPCI circulars, first-day-first-show box office numbers, or the next big OTT premiere.
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