“Kilauea Rules”. The most extreme place we put ours kayakers to paddle till now. Photo location: Big Island, Hawaii. (Photo and caption by Alexandre Socci/National Geographic Photo Contest)

Sharafkhaneh port and lake Urmia. Masoud Ghadiri (Iran). The summer Milky Way is very prominent in this photo. On the galaxy zone, Saturn is located besides the Lagoon nebula. On the right of the horizon, you can see the extreme light pollution of Urmia, which is caused by ever-increasing city development. (Photo by Masoud Ghadiri/National Maritime Museum)

A women wearing a mask to protect from extreme smog visits the Tiananmen Gate in Beijing December 8, 2015 as China's capital issues its first ever "red alert" for pollution. (Photo by Damir Sagolj/Reuters)

A heat-stressed koala waits as a resident pours water on its back on December 19, 2015 in Adelaide, Australia. Adelaide is experiencing an extreme heatwave, with temperatures reaching over 40 degrees for five consecutive days. (Photo by Morne de Klerk/Getty Images)

A vendor sells fish at Central Market in freezing conditions of minus 43 degrees Celsius in the city of Yakutsk, Sakha (Yakutia), Russia on December 13, 2020. The winters in Yakutsk are extremely cold and long and the summers short and warm, with temperatures sometimes rising above 30C. (Photo by Yevgeny Sofroneyev/TASS)

Children riding on donkeys queue to fill their jerrycans with water from a cistern at a make-shift camp for the internally displaced in Yemen's northern Hajjah province on July 12, 2021, amidst an extreme heat wave and severe water shortage. (Photo by Essa Ahmed/AFP Photo)

A street vendor prepares watermelon juice for sale at a roadside stall during a heatwave in Karachi, Pakistan, 17 May 2023. According to the Pakistan Meteorological Department the weather in the Sindh capital will remain extremely hot and dry. (Photo by Shahzaib Akber/EPA/EFE)

People wear clothing to protect them from the heat while riding along a street in Hanoi, Vietnam, 24 April 2019. North and central Vietnam was recently affected by extreme hot weather, with the highest temperatures reaching over 40 degrees Celcius, according to the National Centre for Hydro-meteorological Forecasting. (Photo by Luong Thai Linh/EPA/EFE)