The following Acknowledgements section has been added: 'We recognize early investigative journalism that hypothesized associations between the Groundwater Acts and the air pollution crisis in northwest India (see S. Narain, Straw in the wind. Business Standard, 15 February 2015; https://go.nature.com/36lsmhR). We commend this and similar efforts (for example, A. Kumar, Monsanto's profits, not Diwali, creating smoke in Delhi. The Sunday Guardian, 3 November 2018; https://go.nature.com/3jks92f), and acknowledge the vital role of journalism for shaping and supporting innovative sustainability science. '