The silver lining: the clear blue skies are telling us that it is time to grasp the opportunity to clean the air we breathe. When I heard American pulmonologist Dr Nicholas Marks in an NPR podcast describe the lungs as “these exquisite machines, containers of air that just kind of blow life-giving oxygen into the blood through a thin wall, a membrane”, I understood immediately what he meant by the “poetry of the lungs”. Almost exactly two years ago, I had watched helplessly as my mother – a trained Indian classical music vocalist – struggled to breathe in the terminal stages of the lung cancer that consumed her. In those moments, breathing – an involuntary, effortless activity I’d always taken for granted – embodied this poetry. In my mother’s case, it became an elegy. It is the thinness and suppleness of our lung walls that enables them to expand and contract and pass oxygen smoothly and makes breathing so effortless. “What’s so elegant about it is that that membrane is so thin and delicate,” Dr Marks explained in the podcast. It was this delicate membrane that Dr Marks worried about when he first heard about Covid-19, because what Covid-19 does is inflame that membrane, making the thin, delicate walls of the human lungs very thick. “Suddenly, the lung gets really stiff. And instead of it being really easy to get enough oxygen in, now, suddenly, it requires tremendous work to do it.” Sometimes that even leads to patients needing a ventilator to breathe for them. It’s not just Covid that affects human lungs this way. Many respiratory diseases do – including those triggered by air pollution, like doctors said my mother’s lung cancer was. The only difference is that some of those diseases may not be as immediately lethal as Covid-19 and, more importantly, they don’t spread in bunched up clusters, overwhelming doctors and hospitals at once. But their naturally flatter curve doesn’t mean they kill fewer people.