Indian equity benchmarks BSE Sensex and NSE Nifty50 are likely to make a gap-down start on Monday, tracking weakness across other Asian markets on concerns about rising interest rates and a tightening lockdown in Shanghai that fuelled worries about global economic growth. Singapore Exchange (SGX) Nifty futures -- an early indicator of the Nifty index -- fell as much as 223 points or 1.4 percent to 16,197 ahead of the opening on Dalal Street.