Explanation:

The Foreign exchange reserves of India are India's holdings of cash, bank deposits, bonds, and other financial assets denominated in currencies other than India's national currency, the Indian rupee. The reserves are managed by the Reserve Bank of India for the Indian government and the main component is foreign currency assets.
Foreign exchange reserves act as the first line of defense for India in case of economic slowdown, but acquisition of reserves has its own costs. Foreign exchange reserves facilitate external trade and payment and promote orderly development and maintenance of foreign exchange market in India.
India's foreign exchange (Forex) reserve assets (FCA) stand at $393.743 billion, gold reserves at $20.421 billion, SDRs (Special Drawing Rights with the IMF) of $ 1.544 billion and $2.079 billion reserve position in IMF leading to total Forex reserves of US$ 417.789 billion in the week to January 26, 2018, as per Reserve Bank of India's (RBI) weekly statistical supplement.
Think!
Difference between Market Forex rate and Purchasing Power Parity