Delhi has one of the world’s highest concentrations of PM2.5, the most damaging form of air pollution to human health. Despite this, very few residents choose to purchase and wear pollution masks, that have been shown to filter more than 90% of this pollution for less than $1 USD per mask. To what extent do information frictions or social norms drive this wedge? To what extent do Delhi residents value clean air?

In order to understand the residents demand for masks, particularly in low income groups, we run an RCT on over 3,000 Delhi residents across hundreds of slums in the city. We offer masks at randomized prices, and layer this with a randomized informational video describing the health effects of PM2.5. We also attempt to nudge social beliefs by measuring whether residents have an aesthetic aversion to masks on other people. These treatments allow us to test to what extent information and social norms influence demand for this defensive health behavior.

We then use the decision to purchase a mask, together with quasi-random variation in ambient pollution, to attempt to estimate the willingness to pay for clean air in Delhi — a particularly important parameter to evaluate the costs and benefits of environmental policy.

For this project, the Energy Policy Institute gratefully acknowledges generous research support provided by the Tata Centre for Development (TCD) at UChicago.