What is Goods and Service Tax (GST) and which are the commodities proposed to be kept outside the purview of GST?

It is a destination based tax on consumption of goods and services. It is proposed to be levied at all stages right from manufacture up to final consumption with credit of taxes paid at previous stages available as setoff. In a nutshell, only value addition will be taxed and burden of tax is to be borne by the final consumer. Alcohol for human consumption, Petroleum Products viz. petroleum crude, motor spirit (petrol), high speed diesel, natural gas and aviation turbine fuel& Electricity.

It would be a dual GST with the Centre and States simultaneously levying it on a common tax base. The GST to be levied by the Centre on intra-State supply of goods and / or services would be called the Central GST (CGST) and that to be levied by the States would be called the State GST (SGST). Similarly Integrated GST (IGST) will be levied and administered by Centre on every inter-state supply of goods and services.

Read: Who will decide rates for levy of GST?
Also Read: Which of the existing taxes are proposed to be subsumed under GST?