For 12 hours a day, Raju Misra stands at his snack stall in the world's ultimate pollution blackspot, inhaling toxic fumes and railing against India's politicians for failing to clean up the filthy air.

Anger and alarm are rapidly rising throughout sprawling New Delhi over the air quality that the World Health Organization (WHO) has ranked the most hazardous on the planet.

But life is measurably more dangerous for Misra and the myriad of other street vendors and rickshaw drivers who scratch a living at ground zero -- a bus terminus in the city's bustling Anand Vihar suburb.

Surrounded by major roads clogged with old trucks, along with the interstate bus station, dust-generating construction and not far from a coal-fired power station, the area's air routinely tests far worse than the rest of Delhi.

"In the morning, you can see the smog and smoke in the air from the pollution," Misra said, struggling to be heard over the buses.

"We want the number of cars on the road to be cut. Common people, politicians have to come together to reduce Delhi's pollution," the 60-year-old said from behind his counter.

Delhi has been shrouded in a toxic soup in recent weeks as winter sets in, cutting visibility and pushing PM 2.5 levels more than 10 times over the WHO's recommended safe limit.

These fine particles less than 2.5 micrometres in diameter are linked to higher rates of chronic bronchitis, lung cancer and heart disease as they settle into the lungs and can pass into the bloodstream.

Expert Anumita Roychowdhury said the elderly and children are most vulnerable, particularly those from poor families who live in areas of Delhi highly exposed to the particles.

- Irreversible lung damage -

"Children take in more air than the rest of us. And studies show the damage to their lungs can be irreversible," Roychowdhury, from the Delhi-based Centre for Science and Environment (CSE) think-tank, told AFP.

In the narrow, dark alleys near the bus station where simple homes are clustered, Janki Devi's three children stay indoors after school rather than run around outside.

"I don't send my children to the park to play. I don't want them to fall ill and get fever or cough because of the dust," said the 28-year-old, who has lived in Anand Vihar for 15 years.

Devi, whose husband earns 8,000 rupees ($120) a month toiling in a factory, said she works hard to keep her small home dust-free, but feels powerless once they step outside the front door in the poor neighbourhood.

India's courts are pushing governments to act over the mounting crisis, last week ordering a moratorium in the city on large diesel luxury cars whose fumes are partly blamed for the pollution.

"Why should a rich man be travelling in a diesel car and pollute the environment?" Chief Justice T.S. Thakur told the court, which also banned the burning of garbage.

The court also barred the thousands of diesel trucks that storm through Delhi every night to avoid tolls on roads around the city en route to the rest of the country.

Politicians are belatedly jumping on board, with the Delhi government announcing this month cars will only be allowed on its congested roads on alternate days in January.

There are already more than 8.5 million vehicles on Delhi's roads with 1,400 new cars being added every day as incomes rise.

Experts remain sceptical about how the plan will be enforced given that the police answer to the national government, which shares an acrid relationship with its Delhi counterpart.

But federal Environment Minister Prakash Javadekar, fresh from the Paris climate change summit, insisted last week there will be "no fighting" in efforts to clean up the city for all residents.

"This is the principle we are following to achieve a pollution-free Delhi, and we have started working towards this goal," Javadekar told reporters, adding that work on long-awaited bypasses for the trucks has finally started.

CSE director general Sunita Narain said politicians are under pressure from the courts as well as mounting alarm and criticism of the crisis among broad sections of Delhi society.

"I don't think it's just the middle class or the people who can afford to run away from Delhi (who are concerned). People who can run away from Delhi are running away and putting air purifiers in their homes."

"I think there is a deep worry in Delhi today."

Iran closes capital's schools due to air pollution
Tehran (AFP) Dec 19, 2015 - Iran is to close schools for two days in Tehran, an official said on Saturday, following air pollution three times the acceptable level that has blanketed the city in smog.

Air quality in Iran's capital was the worst for at least nine months this week, media said, and airborne particles from car emissions were at "seven times the standard level".

"All schools will be closed on Sunday in Tehran and in the... towns of Shahr-Rey and Islam-Shahr (both south of the capital)," said environment official Mohammad Hadi Heydarzadeh.

"If the pollution continues, schools will also be closed on Monday," he said on state television.

Traffic will be limited in the city centre and some factories will be closed, media reported.

The official IRNA news agency said that schools will also shut in Alborz province, west of Tehran.

Authorities have asked state employers to grant mothers time off to look after children who will be unable to go to school and urged the elderly, children and sick people to avoid going outdoors.

Emergency services have also been mobilised.

In December 2014, almost 400 people were hospitalised with heart and respiratory problems caused by heavy pollution in Tehran, with nearly 1,500 others requiring treatment.

The Air Quality Index on Monday showed an average reading of 162 -- a "red status" warning that the air is unhealthy for everyone, according to World Health Organization standards.

On Saturday it had dropped slightly to 148, still well above the normal healthy level of between zero and 50.

Peak pollution hit 180 in some areas of Tehran, where poor air is worsened due to high altitudes -- between 1,100 and 1,700 metres (3,600-5,600 feet) above sea level -- in a basin surrounded by mountains.

- 'We cannot breathe' -

Visibility was low Saturday as a grey fog blanketed the capital, a megacity of an estimated 14 million people, and authorities said they expect pollution to worsen in the coming days.

Exhaust fumes from five million cars and almost as many motorcycles that ply Tehran's roads each day make up 80 percent of its pollution, which increases in winter as emissions fail to rise above cold air.

"We cannot breathe. My eyes are itchy and my head hurts," said a taxi driver who only gave his first name, Khosro.

"Traffic is getting worse each day, it is stifling. It is like there is a grey haze hanging over the city. We can't seen the mountains," he said referring to the snow-capped Alborz range that overlooks Tehran.

Iran's government has tried to cut pollution by supplying lower emission fuel in large cities, Masoumeh Ebtekar, a vice president responsible for environmental protection, said this week.

In 2012, pollution contributed to the premature deaths of 4,500 people in Tehran and about 80,000 in the country, the health ministry said.

According to the office in charge of monitoring air quality, the air in Tehran was "pure for only 219 days" during the past 16 years.