Over the past few weeks, a thick brown smog has enveloped Delhi. The pollution is so bad that the capital and surrounding states have shut schools and imposed work-from-home orders. Toxic air at levels 20 times higher than those deemed healthy by the World Health Organization has become a seasonal occurrence in India, causing about 1.6 million premature deaths every year. Madeleine Finlay speaks to Guardian South Asia correspondent Hannah Ellis-Petersen and environmental researcher Karthik Ganesan about what it is like to live with poisonous air – and what needs to be done. Help support our independent journalism at https://www.theguardian.com/sciencepod">theguardian.com/sciencepod