The reserves stood at $571.560 billion as against the all-time high of $642.453 billion seen on September 3 last year, Reserve Bank of India data showed.
Reserves had fallen over $15 billion over the two preceding weeks.
While dollar outflows are the major reason behind this depletion, the change in valuation of reserves held in global currencies other than the US dollar is also partly behind this trend.
RBI does not offer any reason behind the reserves movement.
Out of the current reserves, foreign currency assets stood at $510.136 billion while reserves held in gold were valued at $38.502 billion. The balance is kept with the International Monetary Fund as special drawing rights and reserves.