Calling demonetisation "a big magnum-sized tsunami", West Bengal Finance Minister Amit Mitra on Thursday said India's gross domestic product (GDP) in the current fiscal (2016-17) will take a huge hit on account of demonestisation."In the best case scenario, the GDP for the current fiscal could go down to 5.5 per cent from the 7.5 per cent it had touched in 2015-16," Mitra told India Today news channel."From an estimate that I have, the growth rate in aggregate will fall over 3 per cent and arrive at 4.3 per cent," he said."This means a loss of Rs 4.7 lakh crore of GDP, this will be extinguished. This is in the worst case scenario...the best case scenario is loss of Rs 3 lakh crore," Mitra added.