In the previous reporting week, reserves had increased by USD 1.828 billion to USD 282.95 billion.
Foreign currency assets (FCAs), which form the largest chunk of the reserves, dropped USD 894.2 million to USD 253.609 billion in the week under review, the apex bank said.
FCAs, expressed in dollar terms, include the effect of appreciation or depreciation of the non-US currencies such as the euro, pound and yen, held in the reserves.
India's reserve position with the IMF also fell by USD 177.9 million to USD 2.035 billion in the week under review, RBI data showed.