Mumbai, December 12: The Centre has found itself in a catch 22 situation with respect to Goods & Services Tax (GST) revenue not picking up as per its expectation. As per the information shared in the parliament, the centre’s annual targeted revenues from GST may face a shortfall of 40 per cent. In this backdrop, the 38th GST Council meeting on next week (December 18th) is very crucial as there may be not only hike in the tax rates but also significant overhaul with respect to tax slabs and bring more goods and services under the GST net, which have been exempted so far.