India's spam call problem is how the DND system was built

Two out of three unknown calls Indian users got in 2025 were spam, according to Truecaller’s own count. India has had a Do Not Disturb registry for years. On 18 September TRAI rewrote the spam rules again, the Third Amendment to its 2018 regulations, and the registry still isn’t the fix. Nothing in the new rules changes why.

You have to ask to be left alone

Hold on to one number. In April to June, more than 1.12 billion subscribers had no DND preference registered. Upstox read the same data as only 16% of Indians having the feature switched on. If you never signed up, marketers are allowed to call you, and most of the country never signed up.

Nobody missed this. TRAI prints the figure every quarter. The default is that you can be sold to, and leaving a default alone is what people do. Anyone who has shipped a product knows how that ends.

Where DND does get applied, it works. That quarter 13.16 billion promotional calls went out on the 140 series, and registered preferences blocked 1.48 billion promotional calls. Roughly one in nine of that volume never rang, and it only took the people who bothered to register.

We’d flip it. Everyone starts opted out of promotional calls, and you sign up if you want the offers. Nothing in TRAI’s September release goes anywhere near that.

The calls you hate mostly skip the registry

Registered telemarketers check it. The ones filling your phone mostly don’t. The government told the Rajya Sabha that most unsolicited commercial communication comes from unregistered senders on ordinary 10-digit numbers, which sidestep the registry. TRAI banned that for telemarketing in February 2025. In April to June, operators’ own AI systems still flagged 22.99 billion incoming calls as suspected spam. That’s one quarter.

The part we can’t defend

Under the September rule, numbers in the 140xx, 1600xx and 1601xx series can’t be flagged to you as suspected spam, and call apps like Truecaller can’t block or spam-tag them. You can still block a number yourself. TRAI’s reasoning is that a wrongly labeled call from your bank or a government office costs you something real. For the 1600 series, which is meant for banks and government, that’s a fair worry.

For the 140 series it’s a weak one. That series exists for promotional calls. Truecaller’s CEO says its users ignored 81% of 140-series calls over eight months and block about 400,000 of them a day. Those are his numbers, and he’s in a public fight with the regulator, so weigh them that way. What TRAI did next is checkable, though. Truecaller put a “frequently blocked” badge on those numbers, and TRAI objected and suggested pointing users to the DND app. An app whose users reject these calls all day isn’t allowed to say so, and the answer on offer is the registry that 1.12 billion subscribers haven’t joined.

Reporting is your job

Enforcement runs on complaints. TRAI logged 1.085 million of them in the quarter, about 1.5 per million calls, and 89% came through its DND app. Its chairman has said that most people just block the number on their phone or in a calling app, and that never reaches the regulator. Blocking feels like doing something. To TRAI it doesn’t exist.

The new rules help a little. Three complaints in ten days now trigger action if the operator’s AI has also flagged the sender, down from five. You can appeal a closed complaint within 15 days. Apps with a “spam” button have to forward those reports to the operators’ platform. Good changes, all of them. All of them still wait for you to file.