What is the guiding principle of GST Council?

The mechanism of GST Council would ensure harmonization on different aspects of GST between the Centre and the States as well as among States. It has been provided in the Constitution (one hundred and first amendment) Act, 2016 that the GST Council, in its discharge of various functions, shall be guided by the need for a harmonized structure of GST and for the development of a harmonized national market for goods and services.