The foreign exchange reserves declined by $97.9 million to $322.03 billion for the week ended January 23, Reserve Bank of India (RBI) data showed.
In the previous week (January 16) the reserves went up by $2.66 billion to $322.13 billion.
According to the RBI's weekly statistical supplement, foreign currency assets, the biggest component of the forex reserves, decreased $19.7 million at $297.51 billion in the week under review.
The foreign currency assets had increased by $2.68 billion at $297.53 billion in the previous week (January 16).
The RBI said the foreign currency assets, expressed in US dollar terms, include the effect of appreciation or depreciation of non-US currencies such as the pound sterling, euro and yen held in reserve.
India's reserve position with the International Monetary Fund (IMF) in the week ended January 23 fell by $16.8 million and stood at $1.10 billion.
The value of special drawing rights (SDRs) was lower by $61.4 million in the week under review at $4.04 billion.
Gold reserves for the week ended January 23 was static at $19.37 billion. The reserves had grown by $392 million at $19.37 billion in the week ended January 9.