The Indian telecom market has perennially been plagued by the problem of unsolicited commercial communication (UCC) or pesky calls and SMSs. In 2019, Truecaller identified around 29.7 billion spam calls and 8.5 billion spam SMSs for its users in India. Operators continue to be the top spammers in the country, with 67 per cent of user calls received for upselling of various offers and reminders. However, with the rise of mobile payment systems and a growing economic middle class, banks/fintech-based organisations and telemarketers are emerging as big spammers, recording 10 per cent and 17 per cent of calls respectively.

The problem of pesky calls had become particularly grim in 2018, with users in India receiving the second highest number of spam calls worldwide. Consequently, to deal with the problem, the Telecom Regulatory Authority of India (TRAI) decided to overhaul the existing regulations and came up with the Telecom Commercial Communications Customer Preference Regulations, 2018 (TCCPR, 2018). Its centrepiece was the adoption of blockchain-based distributed ledger technology (DLT). With this, TRAI became the first regulator in the world to harness blockchain technology on such a scale in the telecom sector.

According to the draft regulations, access providers are required to record the consent and preferences of users on a consent register and a preference register respectively, using DLT. Further, the user is given the option to withdraw consent if the consent is abused or is no longer relevant. The DLT system is decentralised and distributed with no single point of trust, and aims to preserve subscriber privacy.

As per TRAI’s guidelines, the implementation of DLT to monitor registered commercial SMS traffic will be completed in 10 phases, including registration and verification of headers, SMS content templates, user consent, user preference and complaints. The first phase of DLT went live on June 1, 2020 and mandated the registration of principal entities and headers on all telecom operators’ portals. Although the deadline for the next phase of activation has not yet been notified by the regulator, the entire onboarding process is expected to be complete by November 2020.

TRAI has noted that, as of the third week of August 2020, around 86,766 principal entities, 146,000 SMS headers and 150,000 content templates have been onboarded to the new blockchain-enabled platform. Moreover, over 4,500 telemarketers with delivery functions and 1,600 telemarketers with aggregating functions have been onboarded to DLT.

Alongside this, in June 2020, TRAI directed all operators to ensure a time-bound registration of entities sending bulk commercial messages, and to assign headers on a priority basis in order to segregate different types of messages. Earlier, in January 2020, the regulator directed telcos to run media campaigns informing users of ways to register their consent/preferences regarding pesky calls and messages, and to create a facility for lodging complaints if the menace persisted. Further, to deter unregistered marketers, if more than 100 messages a day were sent from any SIM card, a premium was to be charged for each extra message. However TRAI removed this premium pricing requirement in June 2020 – a move resisted by most operators.

Recently, TRAI has also shared an inventory of all registered telemarketers and the SMS codes they use for sending commercial communication to subscribers. As per the regulator, most genuine entities have registered themselves, as indicated by the volume of commercial communication traffic, which is now close to earlier levels.

Furthermore, sharing details of the actions taken by service providers against malicious entities, TRAI has noted that since September 2019, access providers have imposed usage caps in more than 130,000 cases. Moreover, warning notices have been issued in over 93,000 cases for first instances of violation, usage caps have been imposed in another 71,000 cases for second instances of violation, and more than 15,000 connections have been disconnected for third instances of violation.

DLT advantages

Industry initiatives

TRAI has recommended blockchain-based DLT as the ideal solution to curb the menace of spamming. Following TRAI’s cue, the telecom sector is now deploying blockchain technology to mitigate the problem of UCC. In February 2020, Bharat Sanchar Nigam Limited (BSNL) announced that it will use blockchain to tackle the commercial calling menace. Recently, the telco issued a warning to its users to refrain from using landline or mobile connections to make marketing calls. In addition, BSNL developed a DLT portal to create a registry of commercial and business entities that wish to communicate with their customers.

Meanwhile, other telcos such as Bharti Airtel, Vodafone Idea Limited (VIL) and Reliance Jio are exploring the use of private numbers for making telemarketing calls. VIL is developing blockchain solutions in partnership with Tanla Solutions. Tanla’s TruBloq solution is available for marketers and brands to register themselves, and for subscribers to provide their preferences and consent.

Similarly, Reliance Jio has partnered with Tech Mahindra to develop a blockchain solution. As part of the deal, Tech Mahindra will provide blockchain technology wherein Reliance Jio can store its subscribers’ data in encrypted format and give users the option to provide consent for the kind of SMSs and calls they would like to receive. Bharti Airtel has already made a similar deployment in a tie-up with IBM.

In August 2020, Truecaller rolled out a spam activity indicator for Android users. The indicator provides detailed statistics about spammers on users’ smartphones. According to the company, at present there are three important trends: spam reports, call activity and peak calling hours. Spam reports show the number of times a user has marked a specific number as spam, while call activity shows the number of calls made by the spamming number. Peak calling hours comprises a time chart that identifies when the spammer is most active. A future update will also show these stats to users, to help them make a decision before accepting the call.

On similar lines, in September 2020, Google introduced a new feature, called verified calls, for Android phones. It helps users distinguish between a genuine business call and a possible spam or scam phone call. The feature displays the caller’s name, logo and reason for calling, as well as a verification symbol indicating that the business has been verified by Google. The tech giant has rolled out the verified calls feature in India, the US, Mexico, Brazil and Spain in the first phase.


Since 2011, around 1.8 million unregistered telemarketers have been disconnected and another 580,000 telemarketers have been blacklisted for UCC. However, despite the availability of facilities such as the National Do Not Call Registry, there has been little respite for users, who continue to be bombarded by unsolicited calls and messages on a daily basis.

DLT thus seems like a sound solution to the spam issue. It will ensure robustness and transparency of the system since any change requires the consensus of each participant in the network. Further, decentralisation leads to increased trust since no single participant or group of participants controls the entire system. The existence of many distributed nodes will also make hacking and the addition of fraudulent records of consent and preferences much harder. Changes made to a ledger will be recorded in real time using DLT.

That said, the DLT architecture is still very new to the Indian telecom sector and stakeholders could well be open to various technological vulnerabilities. Still, this is a step in the right direction and with time, pesky calls will hopefully become a thing of the past.

By Shikha Swaroop