Exposure to air pollution can significantly increase the risk of developing severe mental illnesses to the point where individuals may need to be admitted to hospitals, according to a new study.

The link between air pollution and poorer mental health isn’t new. Past studies have linked increased exposure to air pollution to increased risk of depression, anxiety, schizophrenia, personality disorders, and even suicides. Research suggests the exposure also leads to cognitive delays in children‘s development, and later in life, dementia too.

What is disturbing, however, is the scale of the impact of air pollution on people’s mental health — to the extent that it increases the risk of hospitalization due to mental health by 18%, according to the new study published in the British Journal of Psychiatry this month. This number is referring to the risk of exposure to nitrogen dioxide (NO2) alone.

Touted as “the most comprehensive study of its kind,” the research also suggests that even small increases in NO2 in the atmosphere can lead to a 32% higher risk of needing outpatient treatment for mental health as well. “Even at low levels of air pollution, you can observe this kind of very important effect,” said Ioannis Bakolis, co-author of the study and a biostatistician and epidemiologist at King’s College, London.

The news is alarming for India, where the levels of pollution are not even “low” — and, in addition, pollutants include much more than just NO2.

Related on The Swaddle:

Air Pollution Affects Happiness — But We Don’t Really Understand How

According to the WHO, nine out of the 10 most polluted cities in the world are in India. And a study from 2020 also found that India’s outdoor air pollution levels are as bad in villages as they are in urban areas. A study from March showed that global air pollution levels had dropped in 2020 due to the pandemic slowing the economy down. But with industrial activity picking up again, emissions are rebounding to pre‑Covid19 levels.

Past studies have linked air pollution to miscarriages, anemia, and even shortened lifespans — with India reporting the most infant deaths due to air pollution in the world in 2019. Subsequently, amid the global pandemic, air pollution has also been linked to higher Covid19 mortality rates.

Moreover, in India, NO2, whose principal source is vehicle emissions, is on the rise. A 2021 study by Greenpeace India found NO2 pollution increased in several state capitals between April 2020 and April 2021, with Delhi witnessing a 125% increase, Bangalore by 90%, and Mumbai by 52%.

“Air pollution is modifiable, and on a big scale as well, reducing population-level exposure… We know there are interventions that can be used, such as expanding low-emission zone,” Joanne Newbury, co-author of the study, who researches the impact of urban environments on people’s psychological health at the University of Bristol, said in a statement.

Experts recommend focusing on large-scale communal action to reduce pollution, and subsequently, scale down its impact.

“Mental health interventions at the individual level are actually quite difficult,” said Newbury. At the same time, “identifying modifiable risk factors for illness severity and relapse could inform early intervention efforts and reduce the human suffering and high economic costs caused by long-term chronic mental illness,” the researchers noted.