(IDEX Online) - Surat's vast but long-delayed diamond bourse is now reported be on target for opening next year.It was originally supposed to open in January 2020, according to the Surat Diamond Bourse (SDB) website. That was put back by September 2021, and now to some time in 2022, according to the BusinessToday.In website.The $355m bourse (pictured) will be the world's largest office building, with nine 15-story towers covering a site larger than The Pentagon in the USA.SDB will challenge the dominance of Mumbai's Bharat Diamond Bourse currently the world's largest diamond bourse and home to around 2,500 traders.Surat has long been the capital of diamond manufacturing, handling over 90 per cent of all the world's gems, but the trade has been centered in Mumbai, a five-hour drive away.