NEW DELHI: No app can block phone calls originating from the 1600 number series that are meant for communications by regulated entities and govt to citizens, the Telecom Regulatory Authority of India (Trai) said Friday, adding promotional calls from the 140 series can be blocked by using the do not disturb (DND) registry, but these can’t be tagged or filtered by an app. “Under the Telecom Commercial Communications Customer Preference Regulation, any tagging, blocking or filtering of the calls originating from 1600 series numbers is not permitted,” Trai said. The regulator has mandated the use of 1600 series numbers for service and transaction calls by regulated entities of banking, financial services and insurance entities regulated by RBI, Sebi, IRDAI and PFRDA to their existing customers and by govt entities for govt-to-citizen communication. This has been done to make such calls trustworthy for citizens. The 140 number series is meant for use by registered telemarketers. “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 DND registry,” Trai said. “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,” Trai said. This means 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. Truecaller CEO Rishit Jhunjhunwala has said the number of spam calls made through the 140/1600 number series skyrocketed, with over 5.1 crore calls from both series going unanswered every single day. He said at present Truecaller users actively block 4 lakh calls from the 140 series and 1.25 lakh calls from the 1600 series every day.