Meanwhile, the Disinvestment Ministry wrote to the Prime Minister justifying strategic sale in National Aluminium Company Ltd (Nalco). In its note, the ministry, has said that the profitability of the world's lowest cost alumina producer was on a decline and that it had to diversify in a regime of falling import duties for it to remain competitive. The note was a response by the ministry to a letter from Coal and Mines Minister Uma Bharti to the Prime Minister demanding a reconsideration of the decision to sell Nalco. The PSU's net profit to sales ratio has been falling over the years and stands at I 6 per cent in 2001-02, from a high of 30 per cent just 10 years ago. With aluminium prices declining globally, the profitability of Nalco would also come under strain.