Mumbai, Dec 8 : India's foreign exchange reserves rose to an over four-month high of $604.04 billion as of December 1, according to the latest data released by the RBI on Friday. During the week ended December 1, the forex reserves jumped by $6.1 billion, marking the most substantial gain since the week concluding on July 14. The reserves had cumulatively increased by $7.6 billion in the two preceding weeks. India's foreign exchange reserves increased by $5.077 billion to $595.397 billion for the week ended November 17, the latest data released by the RBI on Friday showed. An increase in the foreign exchange reserves helps the RBI to stabilise the rupee when it turns volatile. The RBI intervenes in the spot and forward currency markets by releasing more dollars to prevent the rupee from going into a free fall when it comes under pressure. Any sharp decline in the country's forex kitty leaves the RBI less headroom to intervene in the market to stabilise the rupee. /IANS