China’s benchmark CSI 300 Index became the world’s worst performer this year after falling 3.8% on Wednesday to close at 2,745.60 points, Bloomberg reported. The index is now down 49% so far in 2008, overtaking Vietnam, which has lost 48% in value. Confidence in the markets has been eroded by concerns about slowing growth and government cooling measures designed to rein in inflation. Banks were among the biggest losers yesterday, with shares in China Merchants Bank and Shanghai Pudong Development Bank slumping 4.1% and 4.7% respectively. Meanwhile, the Shanghai Composite Index fell 2.7% to close at 2,705.87.