Burning lungs and eyes, sore and raw lips, blackened soot-covered buildings, cars and roads, and thick black oily precipitation — these are the devastating real-life scenes from Tehran.

Blackened soot-covered buildings, cars and roads, plumes of thick, black and oily precipitation, toxic air inflaming the lungs, sore and raw lips, and burning eyes — this is what the people of Tehran and its surrounding areas woke up to last week.

As a result of the US-Israeli airstrikes on Iran’s oil infrastructures, huge clouds of toxic smoke were released into the air.

These hazardous clouds then made their return to earth in the form of lethal ‘black rain’ — and the situation is so dire it has prompted international health bodies like the WHO (World Health Organisation) to issue warnings of the health risks to the public.

The IDF confirmed in a statement they had “struck a number of fuel storage facilities in Tehran” which they believed were being used by the Islamic Republic of Iran’s military “to operate military infrastructure, including military entities in Iran”.

After the strikes last week, people living in Tehran complained of difficulties in breathing and burning eyes as oily and pitch-black precipitation fell in and around the Iranian capital due to a number of oil refineries and fuel oil depots being struck by US-Israeli forces.

The strikes came on the same day US President Donald Trump warned “today Iran will be hit very hard” in a post on Truth Social.

Frightening plumes of thick and heavy black smoke have also been spotted over other regions in the Middle East as Iran’s war with the United States and Israel rages on and the Islamic Republic strikes back — targeting a number of Gulf countries in retaliatory attacks. If the situation continues to escalate, Iranians won’t be the only people put at risk by ‘black rain’.

Experts are issuing urgent health warnings to those who have come in contact with ‘black rain’, as exposure to the toxic phenomenon can lead to short- and long-term risks.

Since the US-Israeli strikes on Iran commenced on February 28, BBC has verified at least four confirmed strikes on Iran’s oil facilities around its capital city of Tehran.

Why you should be grateful to have an appendix, AI is turning us all into a brainless army, the world according to fish, and the odds of NASA astronauts returning from Moon - all this and more in our latest science newsletter

Tehran has a population of nearly 10 million people, with millions more inhabiting the surrounding areas.

After the strikes on Iranian oil refineries and depots near Tehran, the city’s residents complained of thick smog and pollution which they claimed was “blocking out the sun”, leaving a strong stench of burning in several parts of the capital city.

Experts swiftly warned that the scale of the pollutants which have already been released into the atmosphere could be “unprecedented” as they cautioned of the lethal health risks to people. The spike in the air pollution was reportedly mostly around the areas around Tehran, where oil facilities were targeted and damaged.

Dr Akshay Deoras, a research scientist at the University of Reading told BBC: “What has happened [in Iran] is definitely unprecedented because it's all coming in from missiles dropping in and airstrikes on oil refineries.”

The people of Tehran ‘can’t breathe’

A 27-year-old teacher in Tehran, Leila, told TIME that the air was “unbreathable” post the first US-Israeli overnight strikes on Iran’s oil infrastructures on March 7.

She said: “Today I was in the car for just 15 minutes, breathing this air. I don’t even know what it is, and now I have a headache. The skin on my face, especially my lips, is sore and raw. It burns and feels like diluted tear gas is in the air. It irritates my eyes, and I keep needing to clear my throat.”

Another woman from Tehran in her 20s told BBC Persian: “I can't see the Sun. There is a horrible smoke. It's still there. I'm very tired.”

Negin (name changed) told The Guardian : “The situation is so frightening it’s hard to describe. Smoke has covered the entire city. I have severe shortness of breath and burning in my eyes and throat, and many others feel the same. But people still have to go outside because they have no choice.”

What exactly is ‘Black Rain’?

People living in Tehran reported downpours of “black rain” after the strikes on the city’s oil facilities last week.

So, what exactly is ‘Black Rain’?

It’s the informal term for rainfall which has been contaminated with a large number of pollutants, which then turns dark or ‘black’.

While normally pollutants tend to get ‘washed out’ of the air when rainfall occurs, the rare phenomenon of ‘black rain’ is a result of high levels of soot, ash, and toxic chemicals combining with water droplets in the atmosphere and falling back to Earth when it rains without getting ‘washed out’.

Dr Deoras explained to BBC Verify: “The raindrops acted like little sponges or magnets, collecting whatever was in the air as they fell, which is why residents observed what's being described as 'black rain'.” It is also a possibility that some of the larger pollutant particles fell out of the air even without precipitation.

Black rain can occur after oil refineries or oil fields catch fire, and can also be a result of volcanic eruptions, wildfires and industrial-grade pollution.

Speaking to BBC, civil and environmental engineering professor at Carnegie Mellon University, Peter Adams, explained how in the case of Iran, microscopic soot was formed as a result of the incomplete burning of hydrocarbons in the fuel oil that was struck.

The burning oil also led to the formation of compounds called polycyclic aromatic hydrocarbons (PAHs) and toxic gases like nitrogen oxides and sulfur dioxide (which cause acid rain), according to the professor.

Health risks after exposure to toxic ‘Black Rain’

After the strikes, the Red Crescent Society in Iran warned the people living in Tehran and its surrounding regions that the ensuing rainfall could be “highly dangerous and acidic”, and could result in “chemical burns of the skin and serious damage to the lungs”.

The microscopic soot — particles of which are roughly 40 times smaller than the average width of a strand of human hair — can embed itself deep inside the lungs and enter the bloodstream, which could cause fatal breathing and heart problems and may even lead to premature death according to experts, as reported by AP . Cancer risk, asthma, pulmonary conditions and heart disease may also be increased due to exposure to PAHs.

The head of WHO, Tedros Adhanom Ghebreyesus, said in an urgent statement issued after the strikes: “Damage to petroleum facilities in Iran risks contaminating food, water, and air — hazards that can have severe health impacts especially on children, older people, and people with pre-existing medical conditions.”

Professor of environmental epidemiology at the University of Leicester, Anna Hansell, told the BBC that “these very intense exposures of particulates have immediate impacts on the lungs”, as she explained that this ‘black rain’ could also have “quite long lasting effects over many years afterwards, on both respiratory systems and increasing cancer risk”.

Whatever the conclusion of this damaging war, one thing is for certain, the highest price of war is always paid by the people.