The atmosphere has changed in Beijing since the Chinese capital’s last Olympics in 2008. While the Summer Games 14 years ago were meant to be a forward-looking celebration of China taking its place on the world stage, the 2022 Winter Olympics have a markedly dourer tone, hamstrung by Covid-19 and political controversy.

But one aspect of Beijing’s atmosphere has clearly improved: the air itself. While the 2008 Games were marked by some of the worst air quality in Olympic history, China’s “war against pollution” has advanced so much since that Olympians this month could glimpse the previously smog-enshrouded mountains surrounding the city. Air pollution in the capital has decreased by 50 percent since the 2008 Olympics, which if maintained will lead to four years of additional life for the average Beijing resident.

But the progress seen in a city that was once synonymous with the term “airpocalypse” is still far too rare. Thousands of miles away in Delhi, air pollution has remained at pervasively high levels for the past few months. The Indian capital’s winter air pollution spike is coming to an end, but the annual cycle — driven by cooler air, cooking and heating fires, seasonal agricultural burning, and the Diwali festival — will persist without further action.

Winter in Delhi is accompanied by a pervasive smell of toxic smoke, by coughing and nausea indoors and outdoors, and by increased hospitalizations for respiratory and cardiac-related illnesses. This past November, Delhi even instituted a partial lockdown for non-Covid reasons, shutting down schools and construction for several days and imposing a work-from-home order for government employees in an effort to reduce air pollution. Throughout the winter into January, Delhi’s Chief Minister Arvind Kejriwal tweeted the city’s bad air pollution levels every day, raising awareness about the issue.

Air pollution in Delhi comes from nearly every source possible: power plants, vehicle emissions, construction dust, agriculture, and the burning of coal for home cooking and heating. All of these activities create particulate matter — minuscule air pollution particles that contribute to cancer, lung and cardiovascular disease, and even cognitive decline.

Read the full article about pollution and air quality by Siobhan McDonough at Vox.