In 2013, when the US Federal Reserve began its programme of "tapering" - that is, ceasing further quantitative easing of monetary policy and reducing its purchases of bonds - the result was a bout of jitters in emerging economies' currency markets. Brazil, India, Indonesia, South Africa and Turkey, which came to be called the "fragile five," were the worst hit.

Five years on, the jitters are back with a vengeance - except that now, many more countries are affected. The standout cases are Argentina and Turkey, whose currencies have depreciated by more than 50 per cent and 40 per cent respectively against the US dollar this year. But the Brazilian real and the South African rand have weakened by about 20 per cent and the Russian rouble by 15 per cent. Among Asian economies, India and Indonesia have witnessed currency depreciation of more than 10 per cent. The Malaysian ringgit and the Philippine peso have also been hit.