Mumbai, Aug. 19 -- Benchmark indices edged higher on Monday as the proposed goods and services tax (GST) revamp lifted hopes of boosting domestic consumption. Adding to the momentumwere India's sovereign ratings upgrade by S&P Global and a temporary relief for nations buying Russian oil. The Nifty 50 index ended Monday at 24,876.95 points, up 1% or 245.65 points, its highest gain since 23 May. The Sensex closed 0.83% higher at 81,273.75 points. Chirag Mehta, chief investment officer at Quantum Mutual Fund, said that while the GST rationalization announced on 15 August could drive up consumption, in the near term reduced collections could strain government finances. However, stronger demand is eventually seen making economic growth more sust...