(IDEX Online) - Tensions between India's two biggest diamond-buying nations - China and the USA - could make matters even worse for Surat's 4,000 manufacturing units, following the "balloon incident".Many are already working at just 60 per cent capacity, with staff paid only for the days they work, and an estimated 20,000 laid off altogether as orders dry up."We do not know how the geopolitical tension will pan out in the coming days. Both the US and China are important markets for us," said Vipul Shah (pictured), chairman of Gem & Jewellery Export Promotion Council (GJEPC) told Economic Times.US fighter jets shot down a suspected Chinese spy balloon over South Carolina two weeks ago after it was spotted drifting. India's gross exports of polished diamonds in December 2022 were down over 28 per cent year-on-year at $1.27bn.