The residents of Delhi are officially living through a public health emergency. Dangerously high levels of PM 2.5, which have exceeded 400 micrograms per cubic meter in the city in recent days, can lead to a host of deadly cardiovascular and respiratory illnesses. These impacts will be experienced across much of India. According to the Air Quality Life Index (AQLI), the life expectancy of the average person in the Indo-Gangetic Plain region of India would be 7.1 years higher if air pollution levels were permanently reduced to meet the globally accepted standard.

In response to this emergency, the Delhi government has launched a massive campaign to distribute 5 million protective masks to its citizens. Although the idea of distributing masks isn’t uncommon, the scale of Delhi’s effort is globally unprecedented. As researchers who study how people defend themselves from air pollution, we have one question: what will this accomplish?

Properly-fitting masks have been shown to dramatically reduce exposure to air pollution and to improve markers of respiratory health. And yet, few people in Delhi wear protective masks, even when traveling through heavily polluted areas. In contrast, masks are a common sight in major cities in countries like China and South Korea, even when pollution levels are just a fraction of the levels typically encountered in Northern India.

Our ongoing work suggests that this is due to two factors: first, awareness about the harmful effects of air pollution is still relatively low; and second, there may be social norms that discourage people from adopting and using their masks. For these reasons, placing masks in the hands of millions – particularly during a public health emergency – might alter the way people think about and defend themselves from air pollution, both today and tomorrow.

Our perspective is informed by emerging experimental research work we have been carrying out through the Energy Policy Institute at the University of Chicago in India (EPIC India). Last year, during the peak pollution season, we interviewed nearly 3,500 individuals living among the large population of Delhi slums, in order to understand how air pollution pervades daily life.

In our data, three patterns stand out. ..