  The use of blockchain in regulatory ecosystems is a promising approach to
address challenges of compliance among mutually untrusted entities. In this
work, we consider applications of blockchain technologies in telecom
regulations. In particular, we address growing concerns around Unsolicited
Commercial Communication (UCC aka. spam) sent through text messages (SMS) and
phone calls in India. Despite several regulatory measures taken to curb the
menace of spam it continues to be a nuisance to subscribers while posing
challenges to telecom operators and regulators alike.
  In this paper, we present a consortium blockchain based architecture to
address the problem of UCC in India. Our solution improves subscriber
experiences, improves the efficiency of regulatory processes while also
positively impacting all stakeholders in the telecom ecosystem. Unlike previous
approaches to the problem of UCC, which are all ex-post, our approach to
adherence to the regulations is ex-ante. The proposal described in this paper
is a primary contributor to the revision of regulations concerning UCC and spam
by the Telecom Regulatory Authority of India (TRAI). The new regulations
published in July 2018 were first of a kind in the world and amended the 2010
Telecom Commercial Communication Customer Preference Regulation (TCCCPR),
through mandating the use of a blockchain/distributed ledgers in addressing the
UCC problem. In this paper, we provide a holistic account of of the projects'
evolution from (1) its design and strategy, to (2) regulatory and policy
action, (3) country wide implementation and deployment, and (4) evaluation and
impact of the work.
