Communities living close to oil fields, where gas is openly burned, are at elevated risk of leukaemia, a BBC News Arabic investigation has revealed.
Dr Saleh comforts 13-year old Fatima Faleh Najem during treatment for leukaemia© BBC
The UN told the BBC it considers these areas, in Iraq, to be "modern sacrifice zones" - where profit has been prioritised over human rights.
Gas flaring is the "wasteful" burning of gas released in oil drilling, which produces cancer-linked pollutants.
BP and Eni are major oil companies we identified as working on these sites.
On the outskirts of Basra, in the south-east of Iraq, lie some of the country's biggest oil exploration areas.
Flared gases from these sites are dangerous because they emit a potent mix of carbon dioxide, methane and black soot which is highly polluting.
For health reasons Iraqi law prohibits flaring within six miles of people's homes, but we found towns where gas was being burned less than two miles people's front doors.
The Iraqi government is aware the impacts this could be having. A leaked Iraq Health Ministry report, seen by BBC Arabic, blames air pollution for a 20% rise in cancer in Basra between 2015 and 2018.
As part of this investigation, the BBC undertook the first pollution monitoring testing amongst the exposed communities. The results indicated high levels of exposure to cancer-causing chemicals.
Using satellite data we found that the largest of Basra's oil fields, Rumaila, flares more gas than any other site in the world. The Iraqi government owns this field, and BP is the lead contractor.
On the field is a town called North Rumaila - which locals call "the cemetery". Teenagers coined the phrase after they observed high levels of leukaemia amongst their friends, which they suspect is from the flaring.
Prof Shukri Al Hassan, a local environmental scientist, told us that cancer here is so rife it is "like the flu".
In 2021, we met Ali Hussein Julood, a 19-year-old childhood leukaemia survivor, from North Rumaila.
The BBC was denied permits to film in Rumaila, so Ali documented his life on the inside.
On clips from his mobile he shows his primary school with smoke from the flares billowing behind it. Ali had to leave school when he was 14 to undergo treatment.
He recounts to us that following years of chemotherapy, one day on his way to hospital, he told his father: "This is it for me. Please say goodbye to my mother."
His father wipes away tears at the memory.
Ali is now in recovery. He told us he asked BP for compensation, as they are the lead contractor at the oil field. But he was met with silence.
Many children in nearby villages have not survived their cancer diagnoses.
Fatima Falah Najem lived 25 miles (40km) down the road from Ali in Zubair oil field, with her parents and six siblings.
Eni - a major Italian oil company - is the lead contractor at Zubair.
Fatima was diagnosed with a type of blood and bone cancer called acute lymphoblastic leukaemia at 11 years old. Exposure to benzene - found in flared gases - can increase the risk of people developing this condition.
From her home we can see the flares blazing almost continuously. The nearest flares are just 1.6 miles (2.6km) from the family's front door.
Fatima's father and her sister watch the toxic smoke from the flares near their home© BBC
Fatima drew the "fiery flames" that surrounded her home whilst in hospital. She told us she enjoyed watching them at night and came to normalise them.
But for her father, watching her get sick, was "like being on fire without being able to extinguish it".
Last year doctors managed to secure her a bone marrow transplant abroad. But by this time she was too sick to travel.
Fatima passed away last November at 13 years old.
The Iraqi health ministry report shows the government is aware of the regions health issues. But Iraq's own prime minister issued a confidential order - which was also seen by BBC Arabic - banning its employees from speaking about health damage caused by pollution.
David Boyd, UN Special Rapporteur on human rights and the environment, told us the people living near oil fields are "the victims of state-business collusion, and lack the political power in most cases to achieve change".Ali Hussein said: "Here in Rumaila nobody speaks out, they say they're scared to speak in case they get removed."
Until now health researchers have been prevented from entering the oil fields to carry out air quality tests.
BBC News Arabic worked with environment and health experts to undertake the first ever independent pollution monitoring in the communities living near the fields.
We tested for cancer-causing chemicals emitted by gas flaring over a two week period.
The air tests from five communities indicated levels of benzene, linked to leukaemia and other blood disorders, reached or exceeded Iraq's national limit in at least four places.
Urine samples we collected from 52 children indicated that 70% had elevated levels of 2-Naphthol, a form of the possibly cancer-causing substance naphthalene.
Dr Manuela Orjuela-Grimm, professor of childhood cancer at Columbia University, said: "The children have strikingly high levels … this is concerning for [their] health and suggests they should be monitored closely."
Prof Shukri collects urine samples from the children living near the oil fields in Basra© BBC
BBC put the findings to Iraq's Oil Minister Ihsan Abdul Jabbar Ismail. He told us: "We instructed all the contracted companies operating in the oil fields to uphold international standards."
The BBC asked BP and Eni for a response to our investigation.
Eni said it "strongly rejects any allegation that its own activities are endangering the health of the Iraqi people".
BP said: "We are extremely concerned by the issues raised by the BBC - we will immediately review those concerns."
Under Poisoned Skies
The deadly impact of the oil giants' toxic air pollution on children and the planet is revealed in this BBC News Arabic investigation from the front line of climate change in Iraq.
The documentary is available to watch now on BBC iPlayer (UK only) and internationally on the BBC website.