(Bloomberg) -- Hundreds of millions of Indians breathe some of the world’s most toxic air all year round. Air pollution in the capital area that’s home to about 30 million people is especially stubborn. In winter, the cold weather actually makes the smog even worse — and potent. This November, the capital saw some of the highest levels of pollution on record, and one measure of pollution in New Delhi frequently exceeds the World Health Organization’s daily recommended limits by a factor of more than 20. Studies show India’s dirty air has been killing about a million or more people a year, a massive figure authorities are still struggling to reduce.
What causes the pollution?
Emissions from vehicles, factories and coal-fired power stations contribute to the dirty air. Construction plays a role, as do households lighting fires for cooking and heating. The burning of stalks and stubble from harvested fields in the states of Punjab, Uttar Pradesh, Haryana and Rajasthan that surround Delhi creates smoke so thick that it can be seen from space. In warmer periods, the smoke can more easily disperse, but cold air can trap toxic particles and cause them to linger close to the ground. It’s a condition known as temperature inversion. This is why air pollution, which is present in Delhi all year, becomes denser and more visible during winter.
Are farm fires the main culprit?
Fires get a lot of the blame, but the reality is more complicated. For example, in 2023 local governments managed to reduce the number of farm fires by as much as 38%, yet pollution in the capital didn’t decline. According to data from the Indian Institute of Tropical Meteorology, the contribution of stubble burning to poor air quality varies but it’s always dwarfed by that of road transportation. There is no scientific consensus on what is the main source of most toxic particles.
How serious is the health risk?
The Lancet medical journal estimated that almost 18% of India’s deaths in 2019 — the year before mortality figures were heavily influenced by the Covid pandemic — were attributable to bad air. The most dire threat to humans is from particles that are 2.5 microns or less in diameter, known as PM 2.5. For reference, a human hair is about 70 microns on average in diameter.
These ultrafine particles can lodge deep in the lungs and possibly enter the bloodstream. Prolonged exposure increases the risk of cardiovascular and respiratory diseases as well as cancer. The latest World Health Organization guidelines set a safety exposure limit, but tens of Indian cities regularly breach it — at times reaching concentrations more than 40 times over the limit.
The death toll from India’s air pollution is elevated even in cities such as Chennai, Bangalore and mountainous Shimla, which were previously thought to have relatively clean air, according to a study in the journal The Lancet Planetary Health.
People outdoors for prolonged periods of the day face the worst impact of pollution. By World Bank calculations, medical conditions and premature deaths linked to pollution cost India 1.36% of its gross domestic product in 2019.
Information from the ground remains scant. Beyond what doctors tell the media, there is no systemic effort to record the health damage caused by pollution each year. However, one survey found that each of the nearly 10,000 respondents living in the capital and its satellite cities had one or more family members suffering from pollution-related ailments, which range from sore throats to headaches to breathing problems.
How is pollution measured?
As scientists better understand the far-reaching health impact of air pollution, access to accurate measurements becomes more urgent. The global community is adopting more sophisticated ways of capturing toxic concentrations and communicating them to the public. In February 2024, the US Environmental Protection Agency tightened the thresholds above which concentrations of fine particles are considered harmful, in line with the latest science. However, Indian air quality standards have not been revised since 2009. They set an acceptable annual threshold for fine particulate matter of 40 micrograms per cubic meter, while the WHO recommends an optimal maximum of 5 per cubic meter.
How does India compare globally?
In 2023, India was home to nine of the top 10 most-polluted cities in the world, as measured by PM 2.5, according to a study by IQAir, which says it collects data from 30,000 air quality monitoring stations in more than 130 countries and territories. Delhi regularly tops the list. India also had 42 of the world’s 50 most polluted cities, where air quality remained consistently above safe levels all year round, it said.
On a country level, India fared a bit better. According to the United Nations Environment Program, the highest death rates for fine particle air pollution in 2021 were in West Asia and Africa. Egypt had some of the highest rates with 250 deaths per 100,000 people, while Iraq was at 150 per 100,000, it said. India was at 91 per 100,000, China was at 100 and the US was at 8.
What is India doing?
In 2019, India launched a national strategy to help clean the air in the most affected cities. But five years later, data indicates little progress. Critics say India’s government is not putting enough money into fixing the problem.
As the smog began to thicken in the capital in October, the government rolled out measures such as spraying mist to capture fine particles and restrictions on motor vehicles to get cars off the roads. The city of Delhi has also spent millions of dollars on so-called smog towers, giant outdoor air purifiers that scientific consensus indicates are ineffective.
Other strategies are more promising. The local government is pushing for the electrification of its bus fleet, aiming to fully move away from vehicles powered by compressed natural gas by 2028. All taxi and delivery companies in the capital will have to electrify their entire vehicle pool by 2030, a move that could go a long way to abate smog.
What are residents doing?
People often complain about the smog on social media, but that’s about it. Even in the thick of pollution season, a survey of 12,000 people found that most just rely on food and drinks that are believed to increase immunity. Less than a third cited using air purifiers, which despite a growth in sales are still considered luxury items. Many have tried “immunity boosting” food or drinks to prevent ailments such as asthma and cancer. A few have been promoted by government officials on social media platforms, which have been met with floods of skeptical comments.
--With assistance from Rajesh Kumar Singh, Debjit Chakraborty and Joel Weber.
©2024 Bloomberg L.P.