New Delhi: The Indian basket of crude oils lost nearly $2 over the weekend, closing trade on Monday at $47.46 after having gone up to $49.35 during the last week. Oil futures fell in trading this week due to the rising economic concerns in Asia and fears of Britain's possible exit from the European Union, which made the US dollar more expensive. The UK Brent crude for August delivery fell back below $50 per barrel, trading early on Tuesday at $49.79 on the London ICE Futures Exchange, and US West Texas intermediate for July delivery traded at $48.35 a barrel on the New York Mercantile Exchange. The US dollar has been boosted by the prospect of a potential hike in US Federal Reserve interest rates and by concerns over Asia's economy, which is pulling down Asian currencies. Concerns about economic growth in China were based mainly on the country's industrial overcapacity and spiralling debt. Oil prices have surged recently over 90 per cent from a multi-year low in February on a weaker US dollar. The price of OPEC -- Organisation of Petroleum Exporting Countries -- basket of 13 crudes fell to $46.25 a barrel on Monday, from $47.76 on the previous trading day on Friday. It closed at $48.02 on Thursday, according to the Vienna-based OPEC Secretariat. The 13-nation cartel, which accounts for 40 per cent of global crude output, said in a statement following its meeting in Vienna earlier this month when it decided against an output cut, that its members were committed to a "stable and balanced oil market and that the market is moving through the balancing process". OPEC member Iran has been ramping up production to its pre-sanctions levels despite the recent supply glut. The Iranian supply has been balanced by disruptions in Canada, Libya, Nigeria and Venezuela. Rebel attacks on oil installations cut Nigeria's production by 10 per cent in May by around 160,000 barrels a day. As a result, OPEC's total crude output fell to 32.71 million barrels a day last month -- from 32.83 million in April -- thus helping drive a rally in oil prices since they touched a 12-year low in January.