The unprecedented decision of the 45-nation nuclear cartel giving exemption to a country which has not signed the Nuclear Non-Proliferation Treaty (NPT) and the Comprehensive Test Ban Treaty (CTBT) is a landmark step in the implementation of the Indo-US nuclear deal that will now go to the US Congress for approval.

"After protracted negotiations, the NSG today adopted an exemption for nuclear exports to India," the Austrian Foreign Ministry said in a statement.

"There is a sense of relief. I am particularly happy that the waiver for India meets with international nuclear non-proliferation architecture," Peter Launsky, Austrian Foreign Ministry spokesman said after an unscheduled meeting of the NSG in Vienna.

Austria, along with Ireland, New Zealand and Switzerland had expressed strong reservations over the waiver being given to India that forced the grouping to have an unscheduled meeting on Saturday after two days of deliberations failed to produce a consensus.

China, which had on Friday night joined these countries, on Saturday did not oppose the waiver but raised some questions regarding specific issues. After the consensus was adopted, Beijing expressed its stated position.

Some changes have been made to the revised draft of the waiver to assuage concerns of the skeptic countries but details of the exact changes were still not available.

Hectic behind the scene negotiations marked the diplomatic triumph for India in which the US played a major part by talking to the naysayers in extended late night discussions.

Manmohan hails NSG waiver

Prime Minister Manmohan Singh hailed the NSG's move to ‘adjust its guidelines’ to enable full civil nuclear cooperation with India, describing it as a ‘forward looking and momentous decision’.

"It marks the end of India's decades long isolation from the nuclear mainstream and of technology denial regime," he said in a statement.

“It is a historic deal,” Manmohan Singh said.

Thanking the US and other member countries for the role they have played in the waiver, Singh said it is in recognition of India's impeccable non-proliferation credentials and its status as a state with advanced nuclear technology. "It will give an impetus to India's pursuit of environmentally sustainable economic growth," he said.

The Prime Minister said the opening of full civil nuclear cooperation between India and the international community will be good for the country and the world.

"We look forward to establishing a mutually beneficial partnership with friendly countries in an area which is important for both global energy security as well as to meet the challenge of climate change," he said.

Indo-US Nuclear deal - Chronology

Following is the chronology of some key developments related to the landmark Indo-US nuclear deal:

1968: India refuses to sign the Nuclear Non-proliferation Treaty (NPT) on the grounds that it is discriminatory.

May 18, 1974: India conducts its first nuclear test.

March 10, 1978: US President Jimmy Carter signs the Nuclear Non-Proliferation Act, following which US ceases exporting nuclear assistance to India.

May 11-13, 1998: India tests five underground nuclear tests.

July 18, 2005: US President George W Bush and Prime Minister Manmohan Singh first announce their intention to enter into a nuclear agreement in Washington.

March 1, 2006: Bush visits India for the first time.

March 3, 2006: Bush and Singh issue a joint statement on their growing strategic partnership, emphasising their agreement on civil nuclear cooperation.

July 26, 2006: The US House of Representatives passes the 'Henry J Hyde United States-India Peaceful Atomic Energy Cooperation Act of 2006,' which stipulates that Washington will cooperate with New Delhi on nuclear issues and exempt it from signing the Nonproliferation Treaty.

July 28, 2006: The Left parties demand threadbare discussion on the issue in Parliament.

November 16, 2006: The US Senate passes the 'United States-India Peaceful Atomic Energy Cooperation and US Additional Protocol Implementation Act' to "exempt from certain requirements of the Atomic Energy Act of 1954 United States exports of nuclear materials, equipment, and technology to India."

December 18, 2006: President Bush signs into law congressional legislation on Indian atomic energy.

July 27, 2007: Negotiations on a bilateral agreement between the United States and India conclude.

Aug 3, 2007: The text of the 'Agreement for Cooperation between the Government of the United States of America and the Government of India concerning peaceful uses of nuclear energy' (123 Agreement) is released by both governments.

Aug 13, 2007: Prime Minister Manmohan Singh makes a suo moto statement on the deal in Parliament.

Aug 17, 2007: CPI (M) General Secretary Prakash Karat says the 'honeymoon (with government) may be over but the marriage can go on'.

Sept 4, 2007: UPA-Left committee to discuss nuclear deal set up.

Feb 25, 2008: Left parties say the UPA would have to choose between the deal and its government's stability.

March 3, 2008: Left parties warn of 'serious consequences' if the nuclear deal is operationalised.

March 6, 2008: Left parties set a deadline asking the government to make it clear by March 15 whether it intended to proceed with the nuclear deal or drop it.

March 7, 2008: CPI writes to the Prime Minister, warns of withdrawal of support if government goes ahead with the deal.

March 14, 2008: CPI (M) says the Left parties will not be responsible if the government falls over the nuclear deal.

April 23, 2008: Government says it will seek the sense of the House on the 123 Agreement before it is taken up for ratification by the American Congress.

June 17, 2008: External Affairs Minister Pranab Mukherjee meets Prakash Karat, asks the Left to allow the government to go ahead with IAEA safeguards agreement.

June 30, 2008: Prime Minister says his government prepared to face Parliament before operationalising the deal.

July 8, 2008: Left parties withdraw support to government.

July 9, 2008: The draft India-specific safeguards accord with the IAEA circulated to IAEA's Board of Governors for approval.

July 10, 2008: Prime Minister calls for a vote of confidence in Parliament.

July 14, 2008: The IAEA says it will meet on August 1 to consider the India-specific safeguards agreement.

July 18, 2008: Foreign Secretary Shivshankar Menon briefs the IAEA Board of Governors and some NSG countries in Vienna on the safeguards agreement.

July 22, 2008: Government is willing to look at "possible amendments" to the Atomic Energy Act to ensure that the country's strategic autonomy will never be compromised, says Prime Minister Singh.

July 22, 2008: UPA government wins trust vote in the Lok Sabha.

July 24, 2008: India dismisses warning by Pakistan that the deal will accelerate an atomic arms race in the sub-continent.

July 24, 2008: India launches full blast lobbying among the 45-nation NSG for an exemption for nuclear commerce.

July 25, 2008: IAEA secretariat briefs member states on India-specific safeguards agreement.

Aug 1, 2008: IAEA Board of Governors adopts India-specific safeguards agreement unanimously.

Aug 21-22, 2008: The NSG meet to consider an India waiver ends inconclusively amid reservations by some countries.