Sensex at the Bombay Stock Exchange started on a positive note today, as investors are keenly awaiting RBI's bi-monthly policy meet outcome due later in the day. However, it shed all its initial gains and the 30-share index was trading flat. It was up by mere 10 points to 31,203 a shortwhile ago.The NSE Nifty also was up by 5 points to 9,642.