Mumbai, May 16 -- India's benchmark Nifty 50 index surged past the key 25,000 mark on Thursday, notching its highest close in seven months, amid signs of easing geopolitical tensions. The rally coincided with the weekly derivatives expiry, pushing volume turnover on the National Stock Exchange to Rs.1.28 lakh crore-the highest since March 27's Rs.1.5 akh crore mark. Besides, short-covering got a lift after US President Donald Trump said India had offered a "zero-tariff" trade deal for American goods. However, after market hours, India dismissed Trump's claim, with external affairs minister S. Jaishankar clarifying that trade talks with the US were still ongoing and "complicated". On Thursday, FIIs net purchased Indian equities worth Rs.5,39...