India could review the goods and services tax (GST) structure to further prune the number of items in the highest slab of 28% as it attempts to stave off a slump in demand. Some states have favoured a reduction in tax rates, worried that the slowdown may get entrenched, and have communicated their concern to the Centre. The GST Council may meet on June 20, ahead of the budget presentation on July 5, and these issues could figure in the discussions.