Air pollution in Delhi has reached its highest level this year, leading to school closures and blanketing the city in dense brown smog.

In some areas, IQAir's live air quality index recorded pollution levels over 30 times the safe limit. India’s pollution control authority reported a 24-hour AQI of 484 in Delhi, classified as "severe plus," the worst recorded this year. By comparison, an AQI of 0-50 is considered "good."

The hazardous air quality has triggered emergency measures, including shutting down most schools, halting non-essential construction, and banning heavy vehicles from entering the city.

The pollution has become an annual blight on the lives of the more than 30 million people who live in Delhi and surrounding areas. Experts say the toxic air quality is reducing life expectancy in the city by an average of seven years.

The smog arrives annually as the weather in the north of India gets colder, trapping toxic pollutants from the tens of millions of cars on the road, as well as from rubbish fires, construction and factory emissions.

The problem is further compounded by stubble fires, when farmers burn their field after harvesting rice to clear them for new crops. The practice is illegal in India and comes with a heavy fine, but according to Safar, a weather forecasting agency under the ministry of earth sciences, these fires have contributed as much as 40% of the pollution suffocating Delhi in recent days. On Sunday, satellites detected 1,334 such events in six Indian states.

Last month India’s supreme court ruled that clean air was a fundamental human right and ordered the central government and state-level authorities to take action. However, most measures have proved ineffective in stopping air quality deteriorating to levels highly dangerous to health.

In a city already riddled with inequality, pollution – and access to clean air – has become one of the great dividing lines between rich and poor. Many in the city are labourers who work outside for long hours during the day and return at night to homes open to the elements, with no air purifiers or protection from pollutants.

Shagun Devi, 34, lives in a small shanty with her husband and two daughters in a crammed neighbourhood of Delhi’s Okhla neighbourhood. “The air in my home is equally polluted as on a road,” she said. “Every year we face these difficult days of pollution and we just have to bear with it. I think it has become a part of our lives.”

Devi works as a domestic help and her husband is a construction worker. She leaves her house at 7am every day and walks 3km to work. Devi said everyone in her family had been sick for the past two weeks since the pollution had worsened and they had no place to seek out clean air, while an air purifier was far beyond their means.

She said: “By the time I reach my workplace, I am already exhausted due to the pollution. I feel short of breath and there is a burning sensation in my eyes and nose. The house I work in has an air purifier. I wanted to buy one for my children. But it costs three months of my earnings.”

For five decades, Sheikh Imamuddin, 70, has made his living selling books on a roadside stall in south-east Delhi. He fears that due to Delhi’s air quality, the job is killing him. He suffers from asthma and struggled repeatedly to speak in the toxic outdoor air, taking long puffs from his inhaler. In the past two weeks he has been to hospital three times.

“I can feel burning sensations in my eyes, lungs and belly. I know this toxic air is killing my lungs further, but I cannot stay home. My earnings are hand-to-mouth,” he said, dusting his books with shaking hands.

“It is a fight to stay alive no matter how little you can,” he added. “People have to breathe even if they know here in Delhi they are breathing poison.”

On Monday the supreme court reprimanded the Delhi government for being slow to introduce emergency pollution measures. Yet, as has become the norm in an annual blame game, the Delhi state government, ruled by the Aam Admi party, blamed the pollution on neighbouring states, governed by the Bharatiya Janata party, which also controls the central government.

Atishi, the Delhi chief minister who goes by a single name, said: “The central government needs to stop playing politics and take decisive action.”

Those who can afford it have been fleeing the city. Aarti Sharma, 41, who works as a tech professional, took a flight to the southern state of Kerala on Monday for what she described as an “escape from Delhi’s pollution”.

“Living in Delhi at this time is absolutely unbearable,” Sharma said. “The pollution is so terrible that I’ve had a continuous headache for the past week. I just couldn’t stay for another day. I feel fortunate that I can afford to do this. The majority of people around us have no options.”

As Delhi’s air turned dangerously toxic, a group of experts gathered on Monday for a press conference at Cop29 in Baku, Azerbaijan, to highlight the urgency of India’s air pollution situation.

Aarti Khosla, the director of Climate Trends, said: “We are all gathered here to talk about bigger issues that affect our climate and countries are dragging their feet so much when the lives and health of millions are at risk. We need to be urgently responsive to the realities of climate change that the world is facing today.”