Mumbai, Jan. 24 -- Amid persistent tightness in liquidity conditions, the Reserve Bank of India (RBI) on Friday announced its third tranche of open market operations (OMOs) for the purchase of government securities worth Rs.1 lakh crore and dollar-rupee buy/sell swaps of $10 billion, to be conducted in February. The central bank will purchase government securities worth Rs.50,000 crore each on February 5 and February 12, whereas it will auction dollar/rupee swaps of three years on February 4, it said in a release. "The Reserve Bank will continue to monitor evolving liquidity and market conditions and take measures as appropriate to ensure orderly liquidity conditions," it said. Besides, RBI also announced a 90-day Variable Rate Repo operation of Rs.25,000 crore to be conducted on January 30. A variable-rate repo auction is a liquidity tool for the central bank, which it uses to inject short-term liquidity into the banking system. Banks borrow funds at a rate determined by the market through an auction process, rather than the fixed repo rate. This is the third tranche of liquidity measures announced by RBI since the first, announced alongside the monetary policy statement in December. The RBI had then said it would conduct OMO purchases worth Rs.1 lakh crore and a dollar-rupee buy/sell swap of $5 billion....