The Congress party will support the Goods and Services Tax ( GST) Bill in the Rajya Sabha if there is acap on the tax. Not necessarily in the Constitution amendment legislation, which will be hard to amend but at least in the main GST Bill, which can be changed by simple majority. This is the party’s bottom line but so far nobody from the government has contacted it to take this discussion forward. The current 200- page GST draft Bill mentioned a rate but does not describe how this can be changed — no formula or any other method. Nor does it term this a cap, implying it can be revised upwards whenever the government wants, without restriction. This is the Congress’ argument. Praveen Chakravarty, senior fellow at IDFC Institute, a Mumbai think tank, puts it this way. He says there has been a 127 per cent increase in petrol taxes and a 386 per cent increase in diesel taxes, both indirect levies, from 2014 to February 2016. The Central Excise Act gives the government the untrammelled pow