No app can block phone calls originating from 1600 number series that are meant for communications by regulated entities and the government to citizens, the Telecom Regulatory Authority of India (TRAI) said in a statement on Friday. The authority also clarified that promotional calls originating from 140 number series cannot be tagged or filtered by an app, and can be blocked only by the DND registry managed by the regulator itself.
"Under the Telecom Commercial Communications Customer Preference Regulation (TCCCPR), any tagging, blocking or filtering of the calls originating from 1600 series numbers is not permitted," Trai said.
The key objective of assigning designated series 1600 for important communications is to make such calls trustworthy for the citizens, the regulator said. On calls starting with 140 number series, TRAI said that it is meant for use by registered telemarketers.
Can block 140, but…
"The customers have the right to allow or block promotional calls originating from 140 series numbers from entities of any or all sectors by registering their preference on the Do Not Disturb (DND) registry," it said.
The regulator said that a customer who has blocked any or all sectors from receiving promotional calls on the DND registry will not receive any calls from 140 series originating from entities of the blocked sectors.
"The customer can register his/her DND preference through multiple means including through TRAI DND App. Any tagging or filtering of calls from 140 series numbers is not allowed except for blocking on the DND registry, as any tagging can mislead a customer who has otherwise allowed receipt of such calls from a sector on the DND registry," it added.
{{/usCountry}}"The customer can register his/her DND preference through multiple means including through TRAI DND App. Any tagging or filtering of calls from 140 series numbers is not allowed except for blocking on the DND registry, as any tagging can mislead a customer who has otherwise allowed receipt of such calls from a sector on the DND registry," it added.
{{/usCountry}}The clarification from the regulator implies that customers will not be able to tag calls from numbers starting with 1600 and the 140 number series as spam, fraud, or any other type of call.
What leading caller ID app says
Truecaller CEO Rishit Jhunjhunwala has said there has been a huge increase in spam calls through 140 and 1600 number series, with over 5.1 crore calls from both series going unanswered every single day, news agency PTI reported.
"Specifically with the 1600 series, reserved for service/transaction related calls, we have seen daily blocking actions triple (up by 208 per cent) since October 2025. A total of 7.4 crore (74 million) manual blocking actions have been taken against these series in the past 8 months," Jhunjhunwala had said in a social media post.
He said that at present Truecaller users actively block 4 lakh calls from the 140 series and 1.25 lakh calls from the 1600 series every day.