NEW DELHI: India’s government and business groups were jubilant on Sunday over a hard-won endorsement from nations that supply nuclear material and technology, a decision that paves the way for a landmark civil nuclear energy accord between India and the United States.

India has been subject to a nuclear trade ban since it first tested an atomic weapon in 1974. The country conducted its most recent test blast in 1998 and has refused to sign non-proliferation agreements.

The 45-nation Nuclear Suppliers Group, which governs the legal world trade in nuclear components and know-how, agreed to lift the ban on civilian nuclear trade with India on Saturday after three days of contentious talks in Vienna and some concessions to countries fearful it could set a dangerous precedent.

India described the agreement as “a forward-looking and momentous decision.’’ “It marks the end of India’s decades-long isolation from the nuclear mainstream,’’ Indian Prime Minister Manmohan Singh said late on Saturday. “The opening of full civil nuclear cooperation between India and the international community will be good for India and for the world.’’

The Confederation of Indian Industry, the country’s top business group, said the decision would open up enormous business opportunities for India as well as help meet its energy requirements.

Chandrajit Banerjee, the confederation’s director-general, called the development a “major confidence-building move’’ for India’s high-technology sector.

US officials have said selling peaceful nuclear technology to India would bring the country’s atomic programme under closer scrutiny and boost - not undermine - international non-proliferation efforts. The civil nuclear agreement, which still requires US congressional approval, will overturn more than three decades of US anti-proliferation policy by allowing America to send nuclear fuel and technology to India, even though New Delhi has refused to sign non-proliferation treaties and tested nuclear weapons.

India, in exchange, would allow international inspections of its civilian nuclear reactors.

The Indian media’s reaction was also effusive. “Nuclear Dawn,’’ said a headline in the Hindustan Times newspaper. “Pariah to power, India joins the big league,’’ it added.

India “enters elite nuclear club after high-voltage diplomacy,’’ The Times of India national newspaper said.

But the Nuclear Suppliers Group’s waiver and the nuclear energy accord between India and the US have come under criticism both in India and abroad.

In India, the right-wing opposition Bharatiya Janata Party has said the deal could undermine the country’s cherished nuclear weapons programme. Communist parties have slammed the India-US deal, saying they don’t want closer ties with the United States.

The Communist Party of India (Marxist) said in a statement on Sunday the waiver represented another step toward a surrender of nuclear independence by India’s ruling coalition.

“The struggle to reverse the agreement is not over,’’ party chief Prakash Karat told reporters.

The International Atomic Energy Agency signed off on the deal last month. The US administration will have to rush to get approval from Congress in the few weeks remaining before lawmakers adjourn for the rest of the year.