Mumbai: India's foreign exchange (forex) reserves dropped by USD 1.22 billion at USD 311.48 billion for the week ended September 30, registering a sharp decline for the second straight week largely due to revaluation of non-dollar assets, official data showed.

The forex reserves had slumped by $4.05 billion during the week ended September 23. The reserves have declined for the third time in the last four weeks under review.

The country's foreign exchange reserves kitty has shrunk by USD 9.30 billion in the last four weeks after swelling to an all-time high of USD 320.78 billion for the week ended September 2.

Foreign currency assets, the biggest component of the forex reserves kitty, fell by USD 1.23 billion to USD 275.69 billion during the week under review, according to the weekly statistical supplement of the Reserve Bank of India (RBI), the country's central bank.

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.

Reserves with the International Monetary Fund (IMF) dropped by USD 345 million to USD 2.61 billion.

However, the value of gold reserves rose by USD 348 million to a record high of USD 28.66 billion.

The value of special drawing rights (SDRs) rose by USD 7 million to USD 4.50 billion during the week ended September 30.