New Delhi, Oct. 4 -- The Quad Summit is unlikely to be held this year, with a mix of domestic issues of member states and trade differences between the US and India and Japan holding up the crucial meeting that was to be hosted by New Delhi, people familiar with the matter said. Before India-US relations were hit by unprecedented strains this summer due to the 50% tariff imposed on Indian goods by President Donald Trump, the four members of Quad were eyeing the possibility of holding the summit in November. But preparations virtually came to a standstill in recent months and there is no clarity as of now on when the summit will be convened, officials of three Quad member states said on condition of anonymity. "A summit this year looks very unlikely. Such meetings require weeks of preparations and even the basic modalities haven't been worked out," one official said. A second official added, "It's very difficult to see President Trump visiting in November, especially given the way trade negotiations between India and the US are poised. A visit is likely to go ahead only if there is a breakthrough on trade issues." The foreign ministers of Australia, India, Japan and the US attended the UN General Assembly in New York last month....