Pedestrians cover their face as they walk along the dusty road in Kathmandu, Nepal February 27, 2017. Nepal has forced 2,500 old vehicles off roads in its capital city of Kathmandu, part of a fight against alarming air pollution levels that have hit nine times World Health Organisation (WHO) limits. Air pollution has been a chronic problem in rapidly growing Kathmandu, which sits in a Himalayan valley and is home to more than 3mn people. (Photo by Navesh Chitrakar/Reuters)

European Space Agency astronaut Tim Peake will return home after a six-month long mission on the International Space Station,on June 18, 2016. Peake was the first British ESA astronaut to visit the ISS and captured hundreds of photographs of the Earth during his mission. Here: “Lots of sun-glint right now during our whole orbit – we haven't seen a sunset for over 3 days”, he wrote. (Photo by Tim Peake/ESA/NASA)

Some of the best entries so far in the 2016 Insight Astronomy Photographer of the Year competition. There are two weeks left to enter, and the winners will be announced in September. Here: Aurora over Laksvatn Fjord, Laksvatn, Norway. The aurora borealis dances in the skies over the town of Laksvatn, with the Milky Way to the left. The image is a single shot with no compositing, only post-processing to bring out the aurora, and some colour corrections. The photographer Matt Walford said: “I love the way the northern lights look like they are just wistfully dancing over the fjord, framed by the mountains on either side”. (Photo by Matt Walford/National Maritime Museum)

These frozen caves seem almost otherworldly as they daylight illuminates them. Matej Kriz’s shots reveal the beauty of the brilliant caves, but he’s also very aware of how deadly they can be. The photographer captured the amazing shots in the Vatnajokull National Park on the Breidamerkurjokull glacier tongue. Here: The ice caves, taken in the Vatnajokull National Park in Iceland, on November 11, 2017. (Photo by Matej Kriz/Caters News Agency)

A view of the fireworks during the Edge at Hudson Yard's 4th of July Celebration at Edge at Hudson Yards on July 04, 2021 in New York City. (Photo by Roy Rochlin/Getty Images for Edge at Hudson Yards)

Photographer holding digital camera during photoshoot of fashion model. (Photo by grinvalds/Getty Images)

The aurora borealis, also known as the northern lights, glow in the sky over St Mary's Lighthouse in Whitley Bay on the North East coast, UK on Friday, May 10, 2024. (Photo by Owen Humphreys/PA Images via Getty Images)

The Knights of Middle England equestrian stunt display team perform ahead of the first match on July 13, 2024. The British Beach Polo Championships, or “sand polo”, returns to the exclusive Sandbanks peninsula near Poole, Dorset. Spectators can appreciate the horsemanship, speed and gladiatorial nature of polo at the largest beach polo event in the world. (Photo by Max Willcock/Bournemouth News)