Why is Syria's starved, opposition-held suburb under attack?

The air strikes came at a rate of one a minute, with horrible results: civilians fleeing collapsing buildings, children trapped under slabs of concrete, paramedics grimly rushing the bloodied victims away on stretchers. Over 250 people have been killed in two days in Eastern Ghouta.

The regime's assault on the opposition-controlled suburbs east of the Syrian capital, Damascus, has been a long time coming. Monday's carnage, which continued throughout Tuesday, was the deadliest in Eastern Ghouta in three years.

Starved and battered by the regime for years, the rebellious area has eluded leader Bashar Assad's control despite being encircled and sporadically bombarded since 2013. Now, it appears the Syrian regime and its Russian backers have decided to retake the territory at any cost.

Much like the opposition-held eastern Aleppo in late 2016, eastern Ghouta is set to become a blood-soaked war theatre as Assad tries to bomb it into submission. Tens of thousands of people live there, along with thousands of hard-line fighters, some of whom will probably fight to the end.

Here's a look at the battle for those suburbs.

What is Ghouta?

Ghouta is an informal name for the suburbs of the Syrian capital, Damascus, that form around the Barada River, and towns in its eastern reaches, including Douma, Kfar Batna and Saqba. 

The residents of eastern Ghouta were among the first to rise up against Assad's rule in 2011. The area was taken over by opposition fighters a year later as the unrest turned into an armed insurgency, then full-blown civil war.

They held on ferociously, determined to preserve the opposition position closest to the capital, denting the narrative of an Assad victory in key places. Today it is the last major opposition enclave in the area, completely surrounded by areas firmly under regime control.

Historically an agricultural area, it has been partially besieged by the regime since 2013 and completely since mid-2017. 

The suburbs endured a devastating sarin gas attack in 2013 that killed hundreds of people. 

Over the years, residential buildings, hospitals, schools, warehouses have all been destroyed.

According to the UN, there are 393,000 residents in Eastern Ghouta, many of them internally displaced from other parts of the country, accounting for 94 percent of all Syrians living under siege today.

UN aid convoys rarely make it inside, and the lack of access has led to severe food shortages, starvation and malnutrition as well as a sharp rise in food prices.

Why has the area eluded Assad for so long?

Thousands of battle-hardened opposition fighters from various factions are entrenched in Eastern Ghouta, including the Army of Islam group based in Douma, and Ahrar al Sham and Faylaq al-Rahman groups. Hayat Tahrir al Sham, a coalition affiliated with al Qaida, also has a presence in the area.

Despite its proximity to Assad's seat of power in Damascus, Syrian troops stretched thin by the scale of the rebellion overlooked Eastern Ghouta for the first few years of the civil war while they focused on recapturing areas deemed more crucial for the government's survival, including Homs, Aleppo and areas near the border with Lebanon.

The opposition in Eastern Ghouta had years to dig in, amassing an abundant reserve of weapons and ammunition from supply lines that stretched to the Syrian desert. Because the region is a farming area — and once the source of most of the capital's sugar, rice, fruits and vegetables — the opposition was able to grow their own food, diminishing the need for supply lines. 

They've also built a labyrinth of secret underground tunnels beyond the reach of airstrikes. Some supplies get in this way, but utilities have been decimated.

What happens now?

With Russia and Iran's help, Assad has turned the war decisively in his favour, recapturing key areas of the country from opposition fighters and Daesh militants.

The renewed assault on Eastern Ghouta is part of a broader escalation on several fronts in recent weeks as Assad and his allies step up their efforts to finish off remaining pockets of resistance — including Idlib province in the north, which houses many evacuees from Aleppo.

The regime has recently sent Brigadier General Suheil al Hassan, also known among his troops as "Tiger," to Ghouta to lead the effort. He has led elite forces to many victories against insurgents since the conflict began, including in Aleppo and most recently in Deir Ezzour against Daesh.

For Assad, victory in Ghouta would go a long way toward ending the seven-year rebellion against him.