At 4 pm on April 20, the benchmark indices, i.e. Sensex and Nifty 50 were trading higher as compared to the previous one. Sensex was trading at 57,037.50, up by 574.35 points or 1.02 per cent while Nifty 50 was trading at 17,136.55, up by 177.90 points or 1.05 per cent.