Indian equities gained in the quarter ended March, just before the deadlier second wave of Covid-19 infections stalled economic recovery.The Nifty 50 rose 5.07% in the January-March period, posting its best fourth quarter since 2007, according to Bloomberg data. The Nifty 500 Index advanced around 7%. The mid- and small-cap indices gained 14-15% each during the three months.Some of the veteran investors used this opportunity to buy o...