How to Stop Spam Calls and SMS in India: DND, 1909 and the 140 Series

To stop most promotional calls and SMS in India, register on the national Do Not Disturb list by calling or texting 1909 from your phone, or through the TRAI DND app. You can block all seven categories of commercial messages or only the ones you choose. It is free, works on every operator, and it will not stop scam calls from ordinary 10-digit numbers, which need a different fix.

• How do I activate DND on my number?
• Full block or partial block?
• What do 140, 1600 and the -P, -S, -T, -G tags mean?
• How do I complain if spam calls continue?
• What DND will not stop

How do I activate DND on my number?

There are three ways, and all of them use the National Customer Preference Register run under TRAI rules:

• Call 1909 from the number you want to protect and follow the voice menu.
• SMS 1909. Sending "START 0" (or "START DND") to 1909 blocks everything.
• The TRAI DND app on Android or iPhone, which also lets you change categories later and file complaints straight from your call log.

You get an SMS confirmation with a registration number. It is not instant, so allow several days before judging whether it worked. Your operator's own app usually has the same setting under its preference or DND section.

Full block or partial block?

Full block stops all commercial calls and SMS from registered telemarketers. Partial block lets you keep the categories you actually want. TRAI's seven categories are:

No.	Category
1	Banking, insurance, financial products, credit cards
2	Real estate
3	Education
4	Health
5	Consumer goods and automobiles
6	Communication, broadcasting, entertainment, IT
7	Tourism and leisure

Our advice: go full block. Nobody in Kakkanad has ever been glad to get a loan offer or a villa project pitch during a meeting, and the messages you do need, such as OTPs, bank alerts and delivery updates, are transactional or service messages that DND is not meant to stop.

What do 140, 1600 and the -P, -S, -T, -G tags mean?

TRAI's February 2025 amendments to the commercial communication rules gave every kind of business message a recognisable label, which makes it much easier to tell what is calling you:

• 140 series: promotional and telemarketing calls. These can be blocked by DND.
• 1600 series: service and transactional calls from banks, insurers and other regulated financial firms. Pick these up; they cannot be blocked under the rules.
• SMS header suffixes: -P for promotional, -S for service, -T for transactional and -G for government messages.

The same amendments bar businesses from making commercial calls from ordinary 10-digit mobile numbers, with disconnection and blacklisting of up to two years for violators.

How do I complain if spam calls continue?

Report it to 1909 by call or SMS, or through the TRAI DND app, with the number or SMS header, the date and a line about what it was. Under the 2025 amendments you have 7 days to complain (TRAI's own FAQ page still mentions 3 days, so do not wait). The amendments also let you complain about unregistered senders even if you never activated DND, and lowered the trigger for action against a sender to 5 complaints in 10 days.

What DND will not stop

DND controls registered telemarketers. It does nothing against a fraudster calling from a regular SIM pretending to be a bank, a courier or the police. For those, report the number on the Chakshu facility on the Sanchar Saathi portal, which we cover in our Sanchar Saathi guide, and read our digital arrest scam guide before you need it. If money has already left your account, call 1930 immediately; our cyber fraud guide explains what happens next. More consumer tech help is in Tech & AI.

Rules note (as of October 2026)

This guide reflects TRAI's Telecom Commercial Communications Customer Preference Regulations as amended in February 2025, and TRAI's consumer FAQ checked in October 2026. Rules and app versions change, so check trai.gov.in for the latest.