A citizen rides in smog on December 20, 2016 in Jinan, Shandong Province of China. Air quality index (AQI) readings exceeded 400 and some schools have suspended classes in Jinan. (Photo by VCG/VCG via Getty Images)

A girl peeps at a gate as primary school students enter to attend an open air class near their school building as part of an initiative from the government following restrictions imposed to control the spread of the Covid-19 coronavirus, in Kolkata on February 7, 2022. (Photo by Dibyangshu Sarkar/AFP Photo)

A goat hops from student to student during a goat yoga class at the University of Tennessee on August 25, 2022 as part of welcome back week. The session was organised by Goat Yoga Nashville. (Photo by Matt Hamilton/Chattanooga Times Free Press via AP Photo)

Ukrainian Air Force officers attend a graduation ceremony at the National University of Defence of Ukraine in Kiev, April 24, 2015. (Photo by Gleb Garanich/Reuters)

A competitor participates in the Tough Mudder challenge near Henley-on-Thames in southern England May 2, 2015. (Photo by Eddie Keogh/Reuters)