NEW DELHI: The piece of news dominating world headlines is that Iran and world powers (known here as the P5+1, namely China, France, Russia, the United Kingdom, and the United States, plus Germany) have reached a framework agreement on Tehran’s nuclear programme. The deal is historic as it is a major step toward ending 12 years of brinkmanship and confrontation.

The deal, although important, is not the final deal, as it is contingent on reaching an agreement by June 30. All sanctions on Iran will remain in place till a final deal is reached. The final deal, in turn, is no guarantee, but the framework agreement is most certainly a huge step in the right direction.

Now that we have established that there is no change to the status quo -- for now -- here is a simple guide to understanding the Tehran nuclear negotiations.

What is the fuss all about?

Simply put, the trouble is over Iran’s capacity to build a nuclear bomb. Iran insists that its nuclear programme is for peaceful purposes, whereas the UN, European Union, the US, and others have all imposed sanctions on the country because well, they don’t believe Tehran’s claim. The negotiations are centred around lifting these sanctions in exchange for Iran agreeing to curbs and limitations to its nuclear programme.

The process has not been easy because the US and others want Iran to prove that it can stuck to the curbs and restrictions before they lift sanctions gradually over time, whereas Iran’s position was that sanctions needed to be lifted immediately as the country needs economic relief and that it should not be levelled with more sanctions when it is in fact complying.

What does this mean?

To understand what sort of curbs and restrictions the US and others have been demanding, a brief physics class is necessary.

There are two types of radioactive materials of consequence here: uranium and plutonium. For each, the process begins with enriching uranium ore. Uranium mined from the earth contains less than 1 percent of U-235 -- the isotope that is used to both fuel reactors and manufacture atom bombs. Centrifuges are needed to separate the isotope from the uranium -- a process defined as enrichment of uranium. For plutonium, the process involved irridating uranium in a nuclear reactor, thereby transforming some of the uranium into plutonium.

(Source: The New York Times)

What’s the problem?

Now that the physics has been established, here is the problem specific to Iran.

Problem Number 1: When uranium is enriched, the centrifuges are used to raise U-235 concentrations. In the west, most power reactors use uranium enriched up to 5 percent. Bomb grade is above 90 percent. Iran has thus far been enriching uranium up to 20 percent.

Problem Number 2: Iran has a stockpile of this low-enriched uranium (for peaceful purposes, they maintain). The problem is that the low-enriched uranium could be fed back into centrifuges and gradually made into highly enriched uranium -- and obviously, the US and others want to make sure that cannot happen.

Problem Number 3: Iran’s “Breakout Time”: “Breakout Time” refers to the amount of time it would take Iran to build a nuclear bomb if it decides to do so. Currently, if Iran’s leaders wake up tomorrow and decide they want a nuke in their hands, it would -- according to a US fact sheet -- take the country two-three months to be able to do so. The US and others want to extend this “breakout time.”

What has been agreed to?

A number of things have been agreed to that relate to the problems above.

Firstly, Iran has agreed to limit enrichment levels ot 3-7 percent and cut its stockpile of that kind of low-enriched uranium from 10,000 kilograms to 300 kilograms for 15 years. Iran has also agreed to reduce the number of centrifuges installed by two-thirds.

Further, as per the framework, Iran’s giant enrichment site at Fordo will be converted into a centre for nuclear physics and technology research. At Natanz -- the country’s main nuclear site -- the number of centrifuges remaining will be cut by half to 5000. At Arak, where the country is building a nuclear reactor that will use natural uranium to produce Pu-239, the deal involves rebuilding the reactor based on a design that will not produce weapon-grade plutonium.

To ensure that Iran doesn’t cheat, greater monitoring and transparency has been agreed to. The International Atomic Energy Agency will have greater access and can investigate sites anywhere in the country. Investigators will also have access to supply chains that support Iran’s nuclear programme, including mines and mills. There will also be continuous surveillance of centrifuge manufacturing and storage facilities.

As per the framework, Iran has agreed to limit its enrichment capacity and research and development for 10 years. Iran will also not build any heavy water reactors for 15 years. The country will limit its stockpile of enriched uranium for 15 years.

The “breakout time” will be extended from two-three months to at least one year.

What has been the reaction?

Largely, the framework has been welcomed. US President Barack Obama praised the outcome, saying: "Today, the United States, together with our allies and partners, has reached an historic understanding with Iran, which if fully implemented, will prevent it from obtaining a nuclear weapon.”

US Secretary of State John Kerry, whilst reiterating that a lot more needed to be accomplished, said: "The political understanding with details that we have reached is a solid foundation for the good deal we are seeking.”

The EU called it a “crucial” decision. "The political determination, the good will of all parties made it possible," EU foreign policy chief Federica Mogherini told a news conference. "This is a crucial decision laying the agreed basis for the final text of joint comprehensive plan of action. We can now start drafting the text and annexes.”

France’s President Francois Hollande welcomed the framework but added that "France will be ensure that a credible, verifiable agreement be established under which the international community can be sure Iran will not be in a position to have access to nuclear arms."

The British government issued a statement saying “This is well beyond what many of us thought possible even 18 months ago and a good basis for what I believe could be a very good deal. But there is still more work to do.”

Russia too welcomed the agreement, saying that it will have a positive impact on security in the Middle East.

Iran’s foreign minister Mohamad Javad Zarif however cautioned: "We're still some time away from reaching where we want to be."

Israel -- that has been opposed to the Iranian deal from the start -- issued a critical statement saying that celebration of the framework was "detached from a wretched reality." Israel further stated that it would continue lobbying world powers against a final deal. The Iran deal, in fact, was a key election issue in Israel, with recently re-elected Prime Minister Benjamin Netanyahu having addressed a joint session of the US Congress over the issue. The address -- made on the invitation of Republicans -- had angered the Democrats and the White House and sent Israeli-US relations plummeting.

Whilst an agreement on the framework has been a major breakthrough, both sides have expressed caution regarding what it means for US-Iran relations and security in the Middle East.

Iran’s foreign minister Zarif said (as quoted by Reuters): “This was an attempt to resolve the nuclear issue ... We have serious differences with the United States… We have built mutual distrust in the past...So what I hope is that through courageous implementation of this some of that trust could be remedied. But that is for us all to wait and see."

The US echoed mutual distrust. A Reuters report stated that “Kerry said the United States remained seriously concerned about Iran’s destabilizing activities in the region. The United States sanctions on Iran for "terrorism, human rights abuses and ballistic missiles will remain in place" under the future nuclear deal.”