New Delhi India\'s central bank sold $7.3 million (Dh26.80 million) of foreign currency in January, official data showed, as the rupee posted its biggest monthly gain on record. The Reserve Bank of India sold a total $12.52 billion last year, according to a report published on its website yesterday, as the rupee weakened 16 per cent against the US dollar. The local currency strengthened 7.3 per cent in January, according to data compiled by Bloomberg, the largest jump since at least February 1973. Central banks intervene in currency markets by arranging purchases or sales of foreign exchange. The rupee, Asia\'s worst performing currency last year, is the region\'s biggest gainer in 2012 with a 6.2 per cent appreciation after the central bank and government took steps to curb speculation and volatility in the foreign-exchange market and attract investment. From gulfnews