Forget Turkey and Argentina. The Indian rupee\u2019s real bugbear is the price of oil. India\u2019s currency had its worst month in three years in August as crude rallied on speculation sanctions on Iran will shrink global supplies. The crude import bill for the world\u2019s fastest-growing oil user surged 76 percent in July from a year earlier to $10.2 billion. That pushed up the trade deficit to $18 billion, the most in five years. \u201cDollar demand for crude heading into Iran sanctions is not helping with rupee pressures,\u201d said Vishnu Varathan, head of economics and strategy at Mizuho Bank Ltd. in Singapore. \u201cDemand for dollars is large, lumpy, and has been on an upward trend given the confluence of rising oil prices and actual demand pick-up for oil.\u201d The rupee is Asia\u2019s worst-performing currency this year, sliding 11 percent and setting a string of record lows, most recently 71.96 per dollar on Wednesday. The pace of the decline has analysts scrambling to revise forecasts, with Mizuho changing its year-end estimate to 70.50 from an earlier prediction of 68.80. Brent, the benchmark of half the world\u2019s oil including India\u2019s, has jumped by more than 70 percent from a low set in the middle of last year. The commodity is currently trading at $77.10 per barrel, a whisker below a three-year high of $80.50 reached in May. Burgeoning oil prices have pushed up India\u2019s monthly oil imports to more than $10 billion in each of the three months through July. They were as little as $5.8 billion in both June and July last year. Elevated oil prices are exerting pressure on both the current account and the fiscal deficit, and that\u2019s weighing on the currency, according to Commerzbank AG. \u201cLast week, there were reports of strong month-end dollar demand, which may have accentuated the rupee\u2019s decline,\u201d analyst Charlie Lay wrote in a research note published Monday. Commerzbank is in the process of revising its rupee forecast and will probably lower it, he said. Rising oil prices will probably see India\u2019s current-account deficit widen to 2.6 percent of gross domestic product in the financial year through March 2019, from 1.5 percent a year earlier, according to Australia and New Zealand Banking Group Ltd. \u201cWith the rupee having reached our year-end forecast of 71.5, the question is how much lower it can go,\u201d head of research Khoon Goh and strategist Rini Sen wrote in a note on Wednesday. \u201cThe currency is still on the expensive side\u201d and current fair value is around 73 per dollar, which suggests it will weaken further, they said. The rupee\u2019s slide has fueled speculation the Reserve Bank of India may revisit a policy employed in 2013 of opening a foreign-exchange swap window to meet the entire daily dollar requirements of the nation\u2019s oil-marketing companies. For now, state-owned refiners Indian Oil Corp., Bharat Petroleum Corp. and Hindustan Oil Corp. are not worried. The RBI hasn\u2019t asked them to defer or stagger their dollar purchases for oil payments, an Indian Oil official familiar with the matter said last month.