Bharat Sanchar Nigam Ltd. & Anr vs Union Of India & Ors

The Supreme Court addressed the nature of mobile phone transactions, determining whether they constitute a sale, a service, or both. The Court held that if the transaction is deemed a sale under Article 366(29A)(d) of the Constitution, states can levy sales tax; if it is a service, only the Central Government can impose service tax. The Court overruled previous High Court decisions, affirming that both sales tax and service tax can apply to different aspects of mobile phone services, thereby allowing both legislative authorities to levy their respective taxes.