QAYYARAH, Iraq — A young boy wearing a large blue backpack waits with his family at an Iraqi Army checkpoint on the northern edge of Qayyarah. He watches expressionless as a military convoy rumbles past; the massive war machines shake the ground. The boy’s face and hands are smeared with black streaks of soot. It’s the same grease that hangs in the air and covers nearly everything around Qayyarah — a result of the oil well fires left burning by the Islamic State. When the Iraqi Army soldier manning the checkpoint begins to argue with the boy’s mother over their identification cards, his younger sister begins to cry, but still his face remains unchanged.

The road through Qayyarah, a city located 37 miles south of Mosul, is packed with vehicles. Military convoys roll toward Mosul as trucks packed with civilians roll away from it. The boy and his family, like the many others attempting to cross into Qayyarah on this late October morning, have fled their homes in villages outside Mosul to escape the ongoing fighting between Iraqi forces and the Islamic State.

A family crosses through the military checkpoint at Qayyarah on Oct. 25.

A man holds his daughter’s hand as they cross the military checkpoint on the northern edge of Qayyarah on Oct. 25.

Displaced civilians arrive at a checkpoint on the edge of Qayyarah.

As reports of Iraqi forces reaching the eastern edge of Mosul begin to emerge this week, Qayyarah is teeming with activity beneath its clouds of burning oil. The city, which was retaken by Iraqi forces in August, has not only become a staging area for the offensive on Mosul; it’s also where civilians fleeing the conflict have come to seek sanctuary.

The U.N. refugee agency (UNHCR) estimates that of the 17,748 civilians displaced around Mosul since Oct. 17, more than 50 percent are sheltered in the Qayyarah area. Some of the families who arrive on this chilly morning appear intact, carrying plastic bags stuffed with clothing. But there are also groups of women accompanied by crying children, all covered in dust.

Yet this hoped-for sanctuary contains risks of its own. Within a few minutes, the wind shifts, and the thick haze from the burning wells blots out the sun. The sky quickly grows so dark that cars passing through the clouds of smoke need headlights to navigate. Some people cover their faces with surgical masks or pieces of cloth, and a lucky few have gas masks.

A child’s hands are covered with soot and grease from the oil well fires set by Islamic State forces that are polluting the air.

A girl walks through the Qayyarah checkpoint with her family as clouds of smoke billow in the sky on Oct. 25.

A man carries his young son as they cross the military checkpoint on the northern edge of Qayyarah on Oct. 25.

As the wind shifts, the sky grows increasingly dark, and more families arrive at the checkpoint on Oct. 25.

As the civilians make it through the checkpoint, they are loaded onto military carriers and transported to a camp for displaced people on the southern edge of Qayyarah. A few of the men are singled out by the Iraqi Army soldiers manning the checkpoint for additional screening, suspected of being Islamic State members, and are shuttled away separately in the back of a white pickup truck.

Iraqi civilians at the camp told

that they fled south for their families’ safety and because there was no food, medicine, or work due to the conflict. Although fleeing carries its own risks, remaining in the grips of the so-called “caliphate” is far more dangerous: Islamic State fighters have reportedly executed civilians in Mosul and are using others as human shields. The U.N. said recently that militants have executed more than 200 people who were allegedly former members of the Iraqi security forces.

A boy tries climbing up a ladder into the back of military truck used to transport people from the checkpoint to refugee camps on Oct. 25.

A young man reaches down to help an older man up a ladder and into a truck.

A group of men distributes food and candy to a family that has just arrived at the checkpoint..

In September, UNHCR estimated that more than 1 million people could eventually be displaced by the ongoing offensive in Mosul and that “some 3.3 million people — equivalent to almost 10 per cent of the population of Iraq — have been uprooted by fighting since the start of 2014.”

Over by the entrance to the checkpoint, a nicely dressed older man wearing a surgical mask hands out sweets and snacks to a newly arrived group of women and children. The newcomers appear worn and tired, covered in dust from their journey. After passing through the checkpoint, they huddle together and share the food by the side of the road. An Iraqi soldier wearing a gas mask and riding atop an armored personal carrier passes them as he heads north toward the fighting. The children clutch the packets of snacks beneath the ashen sky.

Cengiz Yar is a documentary photographer and freelance photojournalist based between Chicago and Iraq.

A girl eats candy as she crosses the military checkpoint with her family on Oct. 25..