1968: India refuses to sign the Nuclear Nonproliferation Treaty (NPT) on the grounds that it is discriminatory.
May 18, 1974: India conducts its first nuclear test. The same year, Nuclear Suppliers Group (NSG) was formed in reaction to the Indian atomic tests to check nuclear proliferation.
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 5 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.
Mar 1/3, 2006: Bush visits India for the first time. 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.
Nov 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."
Dec 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 USA 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 motu 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'.
Feb 25, 2008: Left parties say the UPA would have to choose between the deal and its government's stability.
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 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.
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.
Sep 4-6, 2008: The NSG meets for the second time on the issue after the US comes up with a revised draft and grants waiver to India after marathon parleys.
Sept 11: President Bush sends the text of the 123 Agreement to the US Congress for final approval.
Sept 12: US remains silent over the controversy in India triggered by President Bush's assertions that nuclear fuel supply assurances to New Delhi under the deal were only political commitments and not legally binding.
Sept 13: The State Department issues a fact sheet on the nuclear deal saying the initiative will help meet India's growing energy requirements and strengthen the non-proliferation regime by welcoming New Delhi into globally accepted nonproliferation standards and practices.
Sept 18: The Senate Foreign Relations Committee kicks off a crucial hearing on the Indo-US nuclear deal.
Sept 19: America's nuclear fuel supply assurances to India are a "political commitment" and the government cannot "legally compel" US firms to sell a "given product" to New Delhi, top officials tells Congressional panel.
Sept 21: US financial crisis diverts attention from N-deal as both the Bush Administration and the Congress are bogged down over efforts to rescue bankrupt American banks.
Sept 26: PM Singh meets President Bush at the White House, but were not able to sign the nuclear deal as the Congress did not approve it.
Sept 27: House of Representatives approves the Indo-US nuclear deal. 298 members voted for the Bill while 117 voted against.
Oct 1: Senate rejects killer amendments. Approves the deal with 86 votes for and 13 against the Indo-US nuclear deal.