Tehran - In the urban wasteland of the Iranian capital, Maarya is on the lookout.

From a bridge overlooking the motorway, her eyes follow a slowly crawling stream of cars below. When a police car appears, she dashes towards a building hidden nearby.

Inside are more than 200 Afghan children. Undisturbed by the sharp smell of smog, their smiling faces are spread among various tiny classrooms; in one, a group of young girls learns the English names for farm animals. This all takes place in secret, as Iranian authorities have threatened to shut the school down.

"That's why I spend my lunch breaks by the highway," school principal Maarya, who spoke to Al Jazeera under a pseudonym, explained from her windowless office. "When the police come, I want to warn the kids beforehand ... Recently a group of plain-clothes officers burst into the building. It was terrifying for the kids."

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Maarya, 37, was born in Tehran after her parents fled Afghanistan following the 1979 Russian invasion. For nearly half of her life, she has been working to help educate Afghan children. But it has not been easy: Authorities want to shut down her school, she said, because she does not have the right paperwork to run it and the students are undocumented.

Maarya is not the only one doing this type of work. Human Rights Watch has reported on the phenomenon of unlicensed Afghan schools run by refugees, which tend to charge lower tuition fees and do not ask difficult questions about undocumented children. Iranian authorities have periodically shut down such schools, while at other times issuing warnings. 

Afghan refugees pushed to return home

This is the scene of a forgotten refugee crisis. Afghans have been escaping their country for nearly four decades, whether from the Russians, the Taliban, or the Americans and their allies. The vast majority - a staggering 95 percent, according to the United Nations refugee agency (UNHCR) - ended up in neighbouring Iran or Pakistan, with Iran alone hosting around three million Afghans.

But still, after nearly 40 years, many Afghans say they feel discriminated against by both the state and broader society.

"Afghan is a dirty word," Maarya said. "We are accused of being criminals, lazy, uneducated, stealing jobs, driving up the rent - the usual stuff.

"Not by everyone, of course," she added quickly, gesturing towards a young Iranian volunteer at the school, who was explaining to students the difference between a rooster and a chicken. "Without them, I wouldn't be able to run my school. And there's the local mosque; they offer us shelter when the police come."

Alexey Yusupov, a director with the Friedrich Ebert Foundation in Kabul, says one of the reasons Afghans in Iran face discrimination is the country's economic situation: "Iran is going through a prolonged economic stagnation. The lifting of the sanctions has not stopped this, and the resulting disappointment has flared up anger towards 'parasiting' Afghans even more."

All educational centres ... are obliged by the law to meet certain educational and health standards and requirements, as is practised in many countries in the world.

Ahmad Mohammadi Far, director-general of the Interior Ministry's foreign nationals and immigration department

Last year, Iranian Supreme Leader Ayatollah Khamenei acknowledged the problem of undocumented children in the country. The government says there are believed to be 500,000 Afghan children in Iran who are not officially attending school, while rights groups have estimated that there are around two million undocumented Afghans in total in Iran. Khamenei has said that all children in Iran should be able to attend school, regardless of their residency status.

Maarya, however, has not seen a change in the behaviour of police since Khamenei's statement: "The threats [to shut down our school] are continuing," she said.

Ahmad Mohammadi Far, the director-general of the Interior Ministry's foreign nationals and immigration department, told Al Jazeera that he was not aware of any schools like the one Maarya described, noting that the country's official school system served both registered and illegal refugees.

"All educational centres ... are obliged by the law to meet certain educational and health standards and requirements, as is practised in many countries in the world," Mohammadi Far said, noting that many international bodies, including the UN, "have repeatedly praised Iran for its exceptional services to refugees and hosting large numbers of immigrants for so many years".

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The Iranian government has hosted and provided services to one of the largest and longest-staying refugee populations in the world for decades. There are nearly one million registered Afghan refugees in Iran, in addition to the estimated two million undocumented Afghans.

Cases of serious crimes by Afghan refugees tend to go viral in Iran, putting pressure on the government to expel the refugee population. In June 2012, a group of young Afghan men were accused of gang-raping an Iranian teenager in the central city of Yazd, prompting a furious backlash as Iranians set fire to Afghan refugee neighbourhoods.

Compounding matters, Iran has hosted this population while grappling with its own economic problems, and with little international aid. Earlier this year, as the European Union discussed sending billions of dollars in refugee aid to Turkey, Iran was promised just under $12m in refugee funding.

The UNHCR in Tehran has described Iran's aid to refugees as "exemplary" in several respects, noting that around 350,000 Afghan children were currently enrolled in Iranian primary and secondary schools. Literacy rates have surged, especially for Afghan girls, and the most vulnerable refugees can access public healthcare for as little as $18 a year.

"Regarding education, our priorities include ... ensuring inclusive education for marginalised groups, providing literacy and life skills training, and equipping schools with educational equipment including computers and library books," UNHCR spokesperson Leah Cowan told Al Jazeera via email.

However, such assistance applies only to registered refugees. Since 2003, Afghans in Iran have been required to reapply for refugee status, even if they were granted status in the past. The Iranian government says the goal of this process, dubbed Amayesh, is to update its statistics on a refugee population that has spiralled out of control.

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Yusupov, however, says the complicated and expensive procedure has left many refugees "disintegrated and speechless". Legal avenues for accessing the labour market or registering property remain complex and murky, he said, prompting many towards illegality - a situation that increases the threat of deportation and exploitation. 

As with refugees in other countries who lack the correct papers, "we can't get a driving licence, are not allowed to buy a car or motorbike, can't travel, we're excluded from many schools - we can't even buy a SIM card", Maarya noted.

I can't leave these kids behind, but my entire family is already in Europe, and they are begging me to come. Maybe they're right. I can't live like a refugee all my life.

Maarya, Afghan teacher in Iran

Her son nodded in agreement, noting that he was recently rejected from a university programme that he had long been studying for, simply because "they don't allow any Afghans for technical programmes". But the young man smiled with determination as he displayed a new pair of walking boots: "I saved up for these for months. They are for the road to Europe."

Meanwhile, Maarya stared glumly at the dark walls of her office, decorated with her life's work: photos of her students, childrens' drawings and letters from grateful parents. She says it is too dangerous to return to Afghanistan, but her situation in Iran has grown increasingly precarious.

"The police gave me an ultimatum. They want to pull my school down ... I really don't know what there is left to do," she said. "I can't leave these kids behind, but my entire family is already in Europe, and they are begging me to come. Maybe they're right. I can't live like a refugee all my life."

Source: Al Jazeera