China's yuan hit a four-year low on Wednesday, falling for a second day after authorities devalued it, and sources said clamour in government circles to help struggling exporters would put pressure on the central bank to let it drop lower still, according to Reuters. Spot yuan in China slid to as low as 6.4510 per dollar, its weakest since August 2011, after the central bank set its daily midpoint reference at 6.3306, even weaker than Tuesday's devaluation. The currency fared worse in international trade, touching 6.59 to the dollar. The central bank, which had described the devaluation as a one-off step to make the yuan more responsive to market forces, sought to reassure financial markets on Wednesday that it was not embarking on a steady depreciation.