An interest rate hike by the US Federal Reserve could trigger a flight of capital from India, increasing the demand for the US dollar and pushing rupee further down, neutralising the windfall from falling crude oil prices globally.

But the impact won't be much and the gains from falling crude oil prices would still be significant.

A few days ago, the union petroleum and natural gas ministry's Project Planning and Analysis Cell (PPAC) had estimated that India will save about $39,458 million dollars in the current financial year due to falling crude oil prices. The PPAC estimate said that India's oil import bill will be $73,286 million, down 34.99% from $112,744 million in 2014-15, keeping the quantity more or less at the same level.

If crude oil prices go up by $1 per barrel from $55 per barrel, India needs to shell out Rs 3,513 crore; for every increase of Re 1 per dollar from the Rs 65-per-US-dollar level, the country's oil import bill balloons by Rs 2,972 crore, according to the PPAC.

While the rupee is hovering at around 67 to the US dollar and is a cause for concern, crude oil prices are far from reaching the $55-per-barrel level, given that the global crude oil price of Indian basket was $34.25 on 15 December and is unlikely to change drastically, given the current trends.

In fact, falling oil prices are providing enough leeway for the government to shore up indirect taxes, as is evident from the hike in excise duty on 16 December on petrol by 30 paise per litre and on diesel by Rs 1.17 per litre.

The hike is expected to generate additional Rs 2,500 crore in revenues by March 2016.

The fall in crude oil prices has enabled the Modi government to hike cess on petrol and diesel frequently this financial year.

The result is that excise duties are up sharply by 69% during April to October 2015, to Rs 1,47,685 crore from Rs 87,588 crore during the corresponding period last financial year.

The first India-OPEC dialogue in New Delhi on Tuesday between Dharmendra Pradhan and OPEC secretary general Abdullah al-Badri threw up some interesting comments.

While Badri is said to have told reporters after the meeting that oil prices are likely to rise within a year, Pradhan's cryptic response to India's demand for an Asian discount from OPEC instead of an Asian premium conveyed a lot. "Not cutting the production says so many things," Pradhan said.

The views that crude oil prices could shoot up to $100 per barrel are obviously far from reality.

Clearly, the windfall for the world's third largest importer of crude oil is here to stay.