NEW DELHI: Finance Minister Arun Jaitley said on Thursday that it would be difficult to accept the opposition Congress party’s demand to cap goods and services tax (GST) rate in a constitution amendment bill stuck in parliament. The proposed sales tax, India’s biggest revenue shake-up since independence in 1947, seeks to replace a slew of federal and state levies, transforming the nation of 1.2 billion people into a customs union. The Congress party, the original author of the tax reform, has opposed the bill, calling it ‘flawed’. It wants Jaitley to cap the rate of GST at less than 20 per cent.