Mumbai: Despite covid-19 severely hampering economic activity in the last three months, the April-June period saw the Indian stock markets clock their best quarterly gains since the September quarter of 2009.The rally is largely driven by optimism of economic recovery post reopening of the country and a gush of liquidity flowing into the Indian markets, especially foreign capital.According to a Mint analysis, Indian benchmark indices Sensex and Nifty gained nearly 20% in April-June, as against a decline of 28% and 29% in the previous quarter.Both BSE Midcap and BSE Smallcap indices were up 24.29% and 29.68% respectively in the June quarter.