The benchmark indices posted their biggest single-day fall of the year on Friday on the back of renewed trade concerns between the US and China. The 18 per cent plunge in the shares of Tata Motors, after reporting its biggest quarterly loss, weighed on the market’s performance. The Sensex ended the day at 36,546, down 425 points, or 1.15 per cent — the most since December 21. Ending its five-day gaining streak, the Nifty declined 126 points, or 1.14 per cent, to 10,944. Most Asian markets dropped on fears that US-China relations could worsen as another round of tariff hikes