Indian equity benchmarks Sensex and Nifty50 are likely to make a weak start on Thursday, amid weakness across most other Asian markets. At 7:56 am, Nifty futures trading on Singapore Exchange -- an early indicator of the Nifty index -- were down 13.5 points or 0.1 percent at 17,427.5, having declined as much as 21.5 points to 17,419.5 earlier in the day.