A landmark deal to allow grain exports from Ukraine, which resumed operation on Wednesday after being briefly suspended, has played a crucial role in easing a global food crisis triggered by an offensive by Russian forces in Ukraine.
Brokered by the United Nations and Turkey and signed by Moscow and Kiev on July 22, the agreement created a protected maritime corridor to allow grain shipments to resume for the first time since fighting began in February.
Here's what we know about the deal, known as the Black Sea Cereals Initiative:
Why was it necessary?
When Russian troops launched the offensive in late February, Moscow imposed a blockade on Ukraine's Black Sea ports, banning all agricultural exports. Ukraine is one of the countries with the largest grain production.
The war left 20 million metric tons of grain stranded in Ukrainian ports, sending food prices soaring around the world.
Before the war, up to 90% of Ukraine's wheat, corn and sunflower exports were transported by sea, mostly departing from Odesa. Many developing countries relied heavily on Kiev for grain supplies.
Prices of agricultural commodities were high before the war due to the economic recovery after the COVID-19 virus pandemic. But the conflict pushed the price of grains such as wheat and corn to unaffordable levels for countries that depended on their imports, such as Egypt, Lebanon and Tunisia.
What does the agreement cover?
The agreement ensures the safe export of grain, food products and fertilizers, including ammonia, from three Black Sea ports in southwestern Ukraine: Odesa, Chornomorsk and Pivdennyi.
The first grain ship to leave under the UN-backed deal left on August 1.
According to UN figures as of November 1, a total of 9.7 million metric tons of grain and other agricultural products have been shipped in the first three months of the deal, the vast majority wheat and corn.
Valid for 120 days, the agreement will be renewed on November 19 in a process that could be done automatically without further negotiations.
The UN says extending the agreement is essential for global food security and is calling for it to continue for another year.
Although the initiative is working well, shipments are 40-50% lower than before Russia's attack, the UN says.
How does the deal work?
According to the UN website, the agreement creates a safe corridor between three Ukrainian ports and an area in Turkish waters where ships are inspected before being allowed to continue their journey.
To monitor the agreement, a joint command and control center was established in Istanbul to oversee operations and resolve disputes.
Known as the Joint Coordination Center (JCC), it has four teams of eight inspectors, two from Russia and the same number from Ukraine, Turkey and the United Nations.
These teams inspect, in the Turkish zone, ships carrying wheat, shortly before departure to third countries to ensure that all goods have been checked.
The teams also check empty ships returning to Ukraine to make sure they are not carrying weapons, goods or unauthorized people.
Safe passage
The agreement creates a 10 nautical mile safe zone within which grain ships travel along the corridor with no military vessels, other equipment or drones allowed within that radius.
All vessel movements recorded by the JCC are transmitted to the relevant military authorities to prevent any incidents. Any violations or threats must be dealt with by the JCC.
Early in the war, Ukraine mined its main Black Sea ports to ward off threats of a Russian attack from the sea. Experts say it will take a long time to de-mine all those areas.
The agreement allows Ukrainians to steer ships along safe routes that avoid minefields, in and out of Ukrainian territorial waters.
The deal was put on hold for a while
On October 29, Russia said it was suspending its participation in the deal, accusing Ukraine of using the shipping lane to launch a drone attack on its Black Sea fleet in the Crimean port of Sevastopol.
After a phone call between the defense ministers of Russia and Turkey, the agreement came back into effect on November 2. Moscow said it had received written assurances from Kiev that the corridor would not be used to attack Russian forces.