The Bombay Stock Exchange benchmark Sensex fell by almost 43 points to 20,889in the opening trade today on profit-booking. The Sensex was trading at 20,894, down by over 38 points a short while ago.Brokers said fresh bout of selling by funds and retailers on prevailing levels, coupled with lower than expected quarterly earnings of Telecom major Bharti Airtel weighed down the trading sentiment. In other Asian markets, the Hong Kong's Hang Seng index was quoted lower by 0.33 per cent, while Japanese Nikkei was marginally up by over one per in the morning trade today. In the US, Dow Jones Industrial Average ended 0.53 per cent lower in yesterday's trade.