Explained :Humanitarian Corridors
People Escaping Through Humanitarian Corridor

What are the humanitarian corridors?
The United Nations(UN) considers  humanitarian corridors  a temporary pause of armed conflict.
Both sides of an armed conflict agree to them.They are demilitarized zones  in a specific area and for a specific time.
Russia-Ukraine Agreed Humanitarian Corridor

Why there is a need for humanitarian corridors ?
Via these corridors,civilians can be evacuated or either food and medical aid can be brought to areas of conflict.When conflict areas are under siege and the population is cut off from basic food supplies, electricity and water then the corridors are necessary .
And if a humanitarian catastrophe unfolds because the international law of war is being violated (for example through massive bombing of civilian targets ) humanitarian corridors can provide crucial relief to affected people.
UNICEF providing the relief work

Who is the binding authority of humanitarian corridor?
In most cases, humanitarian corridors are negotiated by the UN. But ,sometimes they're also set up by some local groups. Since all party need to agree to set up the corridors, there is a risk of  political  and military abuse. For example, the corridors can be used to smuggle weapons and fuel into besieged cities which have happened in the history.On the other side, they can also be used by UN observers, journalists and NGOs  to gain access to affected areas where war crimes are being committed.
Destruction Caused By War

What corridors have been set-up in Ukraine?
In eastern Ukraine, a five-hour cease-fire was to be in place on March 5 Saturday, to allow 15,000 residents from the city of Volnovakha and around 200,000 people from Mariupol to leave.
But the initiative failed after a few hours of agreement. The evacuation had been postponed for security reasons as the Russian troops continued to bomb the city and its surroundings ,said the Mariupol city administration .According to media report, Russia however said the corridors set up near Volnovakha and Mariupol had not been used. Russian news agency said "nationalists" prevented the civilians from escaping the warzone and that Russian troops also came under fire during the cease-fire.Ukraine also said that 19 vehicles with humanitarian aid had not been allowed through in the port city of Kherson as Russia had not fulfilled the promise of a corridor .
"First they brought the situation to a critical juncture , and now they rescue us so that we can thank our 'benefactor' for the cameras",Kherson Mayor Igor Kolykhaiev wrote in a Facebook post.
People are sheltering at relief camp

Who gets access to humanitarian corridors?
Access to humanitarian corridors is determined by all the parties to the conflict. Usually, it's limited to neutral actors such as  the UN or aid organizations like the Red Cross. They also determine the length of the area  ,time and which means of transport  ( like buses, trucks or planes )are allowed to use the corridor.
And if the situation is very dire then  humanitarian corridors are only organized by one of the parties to the conflict. In past, this happened with the American airlift after the Berlin blockade by the Soviet Union in 1948-1949.
People Taking Shelter At A Temporary Relief Camp

Where else have they been used in history?
Humanitarian corridors have been put in place since the early mid-20th century. For example, during the so-called Kindertransport from 1938 to 1939, Jewish children were evacuated to the United Kingdom from areas under control of  Nazi.
There is a long history of humanitarian corridors as they were also created during the 1992-1995 siege of Sarajevo, Bosnia and the 2018 evacuation of Ghouta, Syria.
Ground Workers Putting-out the fire caused by missile 

Still today, there are many wars and conflicts where calls for  a pause in fighting  or civilian corridors have been made in vain. For instance, in the ongoing war in Yemen, the UN has so far failed in its negotiations.