I am not writing any theory here but siting an example. Happened to meet a senior manager of Bell Helicopter International India. He was bosting of its spare parts supply to its customers. Bell has ware house in Singapore and has worth 3 Billion USD spare items and will provide it anywhere in India withing 24 hours!! Additionaly it has expert manpower to advise its customers to minimise the cost!!!!
Impressed , I asked if they have any such ware house in India? He was saddened, and informed that the cost of parts will rise as withing India sell will attract 12.33% as VAT!!!!! Plus opening permission needs long time for clearance due heavy bureaucracy and huge ammoundt of bribery!!!!!! So we need USD to buy and demand of US cureency rises!!