Goods and Services Tax (GST) is a proposed system of indirect taxation in India merging most of the existing taxes into single system of taxation. It was introduced by The Constitution (One Hundred and First Amendment) Act 2016.
"Goods and Services Tax" would be a comprehensive indirect tax on manufacture, sale and consumption of goods and services throughout India, to replace taxes levied by the central and state governments. Goods and Services Tax would be levied and collected at each stage of sale or purchase of goods or services based on the input tax credit method. This method allows GST-registered businesses to claim tax credit to the value of GST they paid on purchase of goods or services as part of their normal commercial activity. Taxable goods and services are not distinguished from one another and are taxed at a single rate in a supply chain till the goods or services reach the consumer. Administrative responsibility would generally rest with a single authority to levy tax on goods and services. Exports would be zero-rated and imports would be levied the same taxes as domestic goods and services adhering to the destination principle.
The introduction of Goods and Services Tax (GST) would be a significant step in the reform of indirect taxation in India. Amalgamating several Central and State taxes into a single tax  would mitigate cascading or double taxation, facilitating a common national market. The simplicity of the tax should lead to easier administration and enforcement. From the consumer point of view, the biggest advantage would be in terms of a reduction in the overall tax burden on goods, which is currently estimated at 25%-30%, free movement of goods from one state to another without stopping at state borders for hours for payment of state tax or entry tax and reduction in paperwork to a large extent.
What changes there would be if India launches GST- “The tax rate under GST may be nominal or zero rated for the time being. It has been proposed to insulate the revenues of the States from the impact of GST, with the expectation that in due course, GST will be levied on petroleum and petroleum products.” The central government has assured states of compensation for any revenue losses incurred by them from the date of introduction of GST for a period of five years.