The BSE benchmark Sensex lost over 300 points in the after noon trade today. It was trading at 16573 down by 303 points a short while ago. The fall in Sensex is due to fresh selling in metal, realty, refinery, power and capital goods stocks amid weak Asian cues.The Sensex plunged by almost 390 points to below the 16,500-mark at 1130 hours today.The NSE's 50-share Nifty index was also down by 46.55 points, or 0.92 per cent, to 5,016.05 in morning trade. It was trading 95 points at 4966 a short while ago.Asian stocks declined in early trade amid weak economic data from Japan and Australia that signaled the global economy is slowing ahead of a European summit on the euro zone sovereign debt crisis.The key benchmark indices in Hong Kong, Japan, Singapore, South Korea and Taiwan were down by between 0.5 per cent and 1.54 per cent, while China's Shanghai Composite was up by 0.32 per cent.