(IDEX Online) - The supply of rough diamonds must flow freely again when the world emerges from the coronavirus pandemic, says De Beers boss Bruce Cleaver.In an impassioned open letter, the CEO argues his company has a global, even more than a corporate, responsibility to its workers and customers not to halt production."The continuity of our (mining) operations is central to our people, the local economy and entire nations," he writes.De Beers is currently cutting production by a fifth this year, it canceled Sight 3 and is allowing holders to defer 100 per cent of purchases.But Mr Cleaver is clear that the production and sale of rough should be allowed to resume freely as soon as possible, without external intervention. "We will only sell it when the demand is such that it can create sustainable value for all of us," he writes."However, just as we are not compelling our clients to purchase, we strongly believe it is counterproductive for any part of the industry to compel them not to purchase."His comments follow an appeal by trade bodies in India, the world's cutting and polishing capital, for manufacturers to adopt a voluntary month-long ban on the importation of rough stones, from 15 May.