Authorities in the Indian capital have closed schools, halted construction work and banned non-essential trucks from entering the city after air pollution reached its worst level this season.

Residents of New Delhi choked in toxic smog as air pollution worsened, exceeding 60 times the daily maximum recommended by the World Health Organization (WHO).

So why is this happening?

And can the annual toxic smog in India, Pakistan and Bangladesh be stopped?

How widespread is the pollution?

The level of deadly PM2.5 pollutants in New Delhi – the fine particles in the air that cause the most harm to health – peaked at 907 on Monday morning local time, according to pollution monitors IQAir.

A reading above 15 in a 24-hour period is considered unhealthy by the WHO.

“The people of Delhi are really troubled, they can’t breathe,” Delhi Chief Minister Atishi, who uses only one name, told reporters on Monday.

“I received phone calls all night from people who had to admit their elderly parents to hospital with breathing problems, or from parents looking for steroid inhalers for their children,” she added.

Punjab, Pakistan’s most populous province with 127 million inhabitants, has been hit by an unprecedented wave of pollution since October.

“It’s an apocalypse,” said Ahmad Rafay Alam, a prominent environmental lawyer in Lahore.

Why is this happening now?

Air pollution in northern India is increasing every year, particularly in winter, as farmers burn crop residues in agricultural areas.

Combustion coincides with colder temperatures, which trap smoke in the air.

The smoke is then released into cities, where emissions from cars, trucks and other vehicles add to the pollution.

Emissions from industries and the burning of coal to generate electricity also contribute to smog.

Local weather and topography also play a role.

There are six major airsheds in South Asia: where pollutants from industry, transport and other human activities are trapped and cannot disperse easily.

Lahore in Pakistan, for example, is an airshed that contributes to transboundary pollution.

Under certain wind conditions, 30 percent of pollution in New Delhi can come from Pakistan’s Punjab province, of which Lahore is the capital.

How did the authorities react to the latest smog?

In Delhi, classes for all levels except grades 10 and 12 will be held online and no trucks will be allowed to enter the city except those carrying essential items.

Some older, gas-guzzling vehicles were banned from the city and all construction activities were halted.

Authorities also urged children, the elderly and people with chronic illnesses or respiratory problems to avoid going out as much as possible.

Similar measures have been invoked in the past, with authorities sometimes deploying water sprinklers and smog guns to try to control the haze.

But critics say there needs to be a long-term solution that significantly reduces the pollution itself, instead of measures to mitigate the effects after it has already hit the region.

India’s Supreme Court has ordered local authorities to take “all possible measures”.

“The central and state governments have a constitutional obligation to ensure that citizens live in a pollution-free atmosphere,” the court said.

How do the locals react?

The deterioration of air quality in the Indian capital has sparked outrage among residents on social media.

Many complained of headaches and dry coughs, calling the city “apocalyptic.”

“Everyone has a sore throat,” said Sanjay Goel, a 51-year-old trader in New Delhi.

Others urged authorities to resolve the public health crisis once and for all.

Several studies estimate that more than a million Indians die each year from pollution-related diseases.

Why has South Asia become the global pollution hotspot?

Worsening air pollution is an annual problem for South Asian countries as winter approaches and cold, heavy air traps pollution in a thick layer of smog.

IQAir’s Global Air Quality Report ranked Bangladesh, Pakistan and India as having the highest average PM2.5 concentration in the world in 2023.

South Asian countries have experienced major industrialization and population growth over the past two decades, leading to increased demand for energy and fossil fuels.

And some major contributors are unique to South Asia, including the burning of solid fuels for cooking and heating, human cremation, and the burning of agricultural waste.

The increase in the number of vehicles on the roads as the region develops has also exacerbated the pollution problem.

In India and Pakistan, for example, the number of vehicles has quadrupled since the early 2000s.

New Delhi, ranked the world’s most polluted capital for four consecutive years by IQAir, has 472 vehicles per thousand inhabitants, according to government data.

What is the solution to the pollution crisis?

South Asian countries have begun trying to reduce pollution, developing air quality management plans, installing more pollution monitors and pushing to switch to cleaner fuels.

But these measures have not yet produced significant results.

Experts have called for greater cross-border cooperation between countries like Pakistan, Bangladesh and India to jointly tackle air pollution rather than working in isolation, city by city.

Dust particles can travel hundreds of kilometers, transcending national borders and impacting countries other than those from which they originated.

About 30 percent of the pollution in Bangladesh’s largest cities, for example, comes from India.

Pratima Singh, who has studied air pollution in India for more than a decade, said South Asian countries could emulate the European Union’s model of collaboration to tackle pollution challenges, formalize new policies and share data and best practices.

But that’s a tall order when political relations in the region are tense.

“The technical and scientific community recognizes that air pollution does not need a visa to cross borders,” said Pakistani analyst Abid Suleri of the nonprofit Sustainable Development Policy Institute.

The culprits and problems are the same on both sides of the India-Pakistan border, he said, so it makes no sense for one province to implement measures if a neighboring province on the other side of the border does not adopt the same practices.

ABC/son