India urged citizens to "take the bus" Tuesday as it announced an energy savings drive aimed at knocking $5 billion off its fuel bill, which has risen sharply in recent months.

The nation imports over 75 percent of its crude oil -- which is priced in dollars -- and the cost has climbed dramatically because of high global prices and a plunging rupee.

"We need to do more to conserve fuel or face tougher choices such as steep price increases or even quantitative restrictions," Petroleum Minister Veerappa Moily warned.

The proposed voluntary measures include switching off engines at traffic lights, avoiding fuel-guzzling practices like frequent braking, carpooling, public transport use and tuning up vehicles to improve fuel efficiency.

"We want people to take the bus," Moily said, appealing to citizens to "help our nation in reducing oil imports".

He said he was "trusting in the wisdom of Indians" to adopt more "responsible" motoring habits, even though their reckless driving makes the country's roads among the world's most unsafe.

"We can at least save $5 billion" in fuel costs, Moily said.

He stirred widespread ridicule earlier this month when he said "shutting petrol pumps during the night" was one austerity step being considered to cut imports.

His campaign steered clear of further reducing subsidies on diesel, which accounts for over 40 percent of fuel use.

The Congress-led government, whose popularity has nosedived in the face of a string of corruption scandals, is wary of hiking fuel prices with polls due by May 2014.

It partially deregulated the petrol market in 2010, leading to significant price rises.

"As far as now, there is no proposal to raise prices," Moily said.

Analysts have said India urgently needs to curb fuel consumption -- the biggest item in its import bill.

Premier Manmohan Singh has asked Moily to prepare a plan to cut the oil import bill by $25 billion.

India is struggling to shrink its record current account deficit -- the broadest measure of trade -- which is straining foreign exchange reserves and pressuring the rupee.

While car ownership has risen, driven by increasingly affluent first-time buyers, the main fuel demand comes from the transport sector such as trucks and buses.

India, whose per capita energy consumption is among the world's lowest, has little room to reduce fuel use as it needs to power industry to bolster its fast-slowing economy.

Moily was cagey about a proposal he has made to save $8.5-billion in import costs by boosting oil purchases from Iran, hit by US-led sanctions over its contested nuclear program

He told reporters India has a "serious engagement with Iran" and "continues to deal" with the Islamic Republic but that he did not want to comment further.

US President Barack Obama and Singh are due to meet in Washington later this month and India has been walking a diplomatic tight rope over its Iranian oil purchases.

New Delhi can pay for Iranian oil in rupees instead of dollars, sparing India's foreign exchange reserves.