Indian equity benchmarks BSE Sensex and NSE Nifty50 are likely to make a gap-down start on Tuesday, amid a mixed trend in global markets as caution persisted on inflation and aggressive hikes in COVID-era interest rates. Singapore Exchange (SGX) Nifty futures — an early indicator of the Nifty index — fell as much as 145.5 points or 0.9 percent to 16,426.5 early on Tuesday, suggesting a gap-down opening ahead on Dalal Street.