Serbian police officers of the Special Anti-Terrorist Unit pose for a picture in their base outside Belgrade October 8, 2014. When the killing of an unarmed black teenager by a white policeman in Ferguson, Missouri, in August sparked sometimes violent protests, the response of police in camouflage gear and armoured vehicles wielding stun grenades and assault rifles seemed more like a combat operation than a public order measure. Some U.S. police departments have recently acquired U.S. military-surplus hardware from wars abroad, but there are many law enforcers around the world whose rules of engagement also allow the use of lethal force with relatively few restrictions. But for every regulation that gives police wide scope to use firearms, there is another code that sharply limits their use. In Serbia, police may use measures ranging from batons to special vehicles, water cannon and tear gas on groups of people who have gathered illegally and are behaving in a way that is violent or could cause violence, but they may use firearms only when life is endangered. (Photo by Marko Djurica/Reuters)

A woman, wearing a traditional Sevillana dress, performs as she asks for alms in downtown Malaga, Spain, April 28, 2016. (Photo by Jon Nazca/Reuters)

A local wears a plastic water bottle with a cutout to cover her face, as she walks on a footbridge in Hong Kong on January 31, 2020, as a preventative measure following a virus outbreak which began in the Chinese city of Wuhan. The World Health Organization, which initially downplayed the severity of a disease that has now killed 170 nationwide, warned all governments to be “on alert” as it weighed whether to declare a global health emergency. (Photo by Anthony Wallace/AFP Photo)

Young women flash the victory sign in front of a bonfire as Turkish Kurds gather during Newroz celebrations for the new year in Diyarbakir, southeastern Turkey, on March 21, 2017. Newroz (also known as Nawroz or Nowruz) is an ancient Persian festival, which is also celebrated by Kurdish people, marking the first day of spring, which falls on March 21. (Photo by Ilyas Akengin/AFP Photo)

16-year-old panda, Ye Ye, rests in an enclosure at the Wolong Nature Reserve, a conservation center that trains pandas for release into the wild. This image was published in the August 2016 National Geographic magazine as part of the “Pandas Gone Wild” story. (Photo by Ami Vitale/National Geographic Creative)

Behaviour: Mammals category. Giant Gathering by Tony Wu, USA. Dozens of sperm whales mingled noisily off Sri Lanka’s northeast coast, stacked as far down as Tony could see. This was a congregation of dozens of social units, like a gathering of the clans. Aggregations like this could be a critical part of the whales’ rich social lives but are rarely reported. Some two thirds of the population was wiped out before commercial whaling was banned in 1986. This kind of major gathering could be “a sign that populations are recovering”, says Tony. (Photo by Tony Wu/Wildlife Photographer of the Year 2017)

Tigray refugees who fled the conflict in the Ethiopia's Tigray arrive with their donkey on the banks of the Tekeze River on the Sudan-Ethiopia border, in Hamdayet, eastern Sudan, Saturday, November 21, 2020. (Photo by Nariman El-Mofty/AP Photo)

Farmers play tug of war in a paddy field on National Paddy Day in Tokha village, on the outskirt of capital Kathmandu, Nepal, 29 June 2021. Nepal is celebrating National Paddy Day with various events on 29 June. On this day, known as Asar Pandra, farmers begin the annual rice planting season and mark the day with various festivities such as preparing rice meals with muddy water, mud being a symbol for a prosperous season. Sixty percent of Nepal's agriculture industry relies on monsoon rain while 40 percent is carried out through irrigation. Agriculture is a major contributor to the country's GDP. (Photo by Narendra Shrestha/EPA/EFE)