How did one of the poorest countries in the world get to that point? It's a complicated story, one that involves warring regional superpowers, terrorism, oil and an impending climate catastrophe.
But in some ways, it's also a simple one. Lots of people outside of Yemen are fighting for control and influence. And lots of the people within the country are paying the price.
How did the current political crisis start?
Like many conflicts in the Middle East, Yemen’s struggle started with the Arab Spring. In November 2011, after protests, the country’s longtime dictator Ali Abdullah Saleh agreed to hand power to his deputy, Abed Rabbo Mansour Hadi.
At the time, Saleh's outster was seen as a victory for democracy. But over the next couple of years, Hadi struggled to lead effectively. The country was plagued with unemployment, food insecurity and corruption. Its people also faced attacks from the al-Qaeda affiliate based in Yemen. Hadi also struggled with a skeptical army (many top lieutenants had remained loyal to Saleh) and a separatist movement in the south.
The Houthi rebel group, which supports the country's Shiite minority, took advantage of Hadi's weaknesses. The group staged a coup, taking control of the country’s north. Many Yemenis supported the Houthis, at least initially. They were frustrated by the government’s weakness. When the Houthis decided to take control of the Yemeni capital of Sanaa, thousands of civilians pitched in, setting up street camps and roadblocks.
By February 2015, the Houthi controlled Sanaa, and Hadi had escaped to the port city of Aden.
How did Saudi Arabia get involved?
Yemen’s northern neighbor watched warily as the Houthis took over. Saudi Arabia is majority Sunni, and it was leery of allowing a Shiite group to gain control of a border country, particularly one allied with its enemy Iran. Quickly, Saudi Arabia teamed up with eight other Sunni Arab states to try to beat the group back and restore Hadi to power. Over the next two years, the coalition launched an extensive airstrike campaign. Thousands of bombs have been dropped; many have hit and killed civilians. According to research, out of about 8,600 of those attacks, 3,577 hit military sites, and 1,510 struck residential areas, school buildings, hospitals and other civilian sites.
According to one report from the United Nations, at least 10,000 Yemenis have been killed in the violence; 40,000 more have been injured.
The airstrikes haven’t resulted in much progress. Government forces were able to retake Aden, but only after a fierce, four-month battle that left hundreds dead. That victory gave the government a stronghold from which to take control of much of the south.
The Houthis still maintain control of much of the north. As the BBC explained, “Despite the air campaign and naval blockade continuing unabated, pro-government forces have been unable to dislodge the rebels from their northern strongholds, including Sanaa and its surrounding province."
Adding to the strife, al-Qaeda also controls some parts of Yemen, and the Islamic State is active there, targeting the government-controlled south.
What prompted the blockade?
In early November, Saudi Arabia intercepted a ballistic missile near Riyadh, its capital. Officials allege the weapon was fired by the Houthis and that it was provided to them by Iran. Crown Prince Mohammed bin Salman called the launch a “direct military aggression” that could be “considered an act of war.” In retaliation, Saudi Arabia sealed all entry via land, air and sea in an effort, it says, to prevent Iran from providing any more weapons to its rebels.
Why is it a blockade so dangerous in Yemen?
In addition to this political crisis, Yemen is facing an environmental catastrophe. Nearly 90 percent of the country is classified as arid or desert. Water is scarce — Yemen has one of the lowest rates of per-capita water availability in the world, about two percent of the global average. Rapid depletion of groundwater resources means the water table has dropped quickly. Droughts and desertification have made an already challenging agricultural scene nearly impossible. Much of the little usable agricultural land is used to grow qat, a cash crop and mild stimulant chewed by about 70 percent of Yemeni men.
Before the civil war broke out, Yemen imported nearly 90 percent of its food, mostly by sea. Seven million Yemeni people rely entirely on imported food. Because of the fighting, importing food has become much more difficult. Many shipping companies simply won't send supplies anymore. Even before the blockade, those who ship supplies could face massive delays and mandatory searches by coalition warships.
After an international outcry, the Saudis loosened the blockade on Yemeni ports — a bit. Saudi Arabia said it would allow aid to enter government-controlled ports in three cities. But aid groups and the United Nations say it's not nearly enough.
What kind of humanitarian toll could the blockade take?
According to the United Nations, Yemen is in urgent need of medicines, vaccines and food. The supplies “are essential to staving off disease and starvation,” the organization said. “Without them, untold thousands of innocent victims, among them many children, will die.” A joint statement from the heads of the World Food Program, UNICEF and the World Health Organization called the situation in Yemen "the worst humanitarian crisis in the world."
They warn that 3.2 million people are at risk of famine, and 150,000 malnourished children could die in the next month. (Right now, according to Save the Children, 130 children are dying every day in Yemen.)
A least 17 million other people, including 11 million children, are in desperate need of humanitarian supplies. The shortage of medicine and clean water has also led to the spread of disease. The country is now in the throes of the fastest-growing cholera epidemic ever recorded. Nearly 900,000 people have been affected, according to U.N. figures.
Is peace possible?
Right now, it’s hard to imagine. The United Nations has organized three rounds of peace talks. All have collapsed, spurring in an escalation in fighting and civilian casualties. Hadi’s government is demanding that the rebels withdraw from all areas they control as a precondition for talks, making success unlikely.