The world’s biggest office complex opened yesterday in India. At 620,000 square metres, the Surat Diamond Bourse in Gujarat is bigger than the Pentagon. It’s also a bold bid by India to establish itself as a new global diamond manufacturing and trade hub; and by Narendra Modi, the prime minister, to give his home state a leg up over Mumbai. For now, Mumbai remains India’s dominant diamond export centre, but Surat already cuts and polishes about 90 per cent of the world’s rough stones, Bloomberg reports. Most of them came from Siberia, at least until sanctions were imposed on Russia’s Alrosa diamond giant last year, but a lot of Australian diamonds are polished in Surat too. The goal is to attract “dealers from all over the world [to] do business from a secured and centralised place,” says Eli Izhakoff, honorary president of the World Federation of Diamond Bourses. What they make of that in Antwerp and Tel Aviv remains to be seen. The SDB has nine towers and 4,700 offices. So far only 130 of them are occupied.