(IDEX Online) - Diamond manufacturers in India have cut their output, reduced working days from 12 hours to eight and are closing factories for two days a week as US sanctions on Russian diamonds begin to bite.The vast majority of the world's diamonds are cut and polished in Surat, but only about 10 per cent of Russia's diamond output is imported directly.Last week the US added Alrosa, the diamond miner part-owned by Russian government, to its list of Specially Designated Nationals (SDN) list. That excludes it from the US banking system and is bars it from trade with US citizens. "US is a big market for us," Vipul Shah, vice-chairman of the Gem & Jewellery Export Promotion Council (GJEPC) told India's Economic Times."There is nervousness in the market now. Everybody is taking a cautious step and the industry is currently on a wait-and-watch mode."Ramesh Zilariya, president of the Diamond Workers' Union in Gujara,t said: "There is a nervousness in the US market, our biggest buyer. This has forced the cutting and polishing units to cut down production. As result, our wages have got impacted. We used to work seven days a week. Now it has been brought down to five days a week."