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)

Children eat watermelons to meet the “beginning of autumn” at a kindergarten in Handan, China on August 7, 2015. Chinese tradition to eat watermelons or peaches before that day symbolises “biting away summer”. The solar term ‘beginning of autumn’ falls on 8 August this year. (Photo by Xinhua/REX Shutterstock)

A drunk student is sick on the street watched by a police officer following a night of heavy drinking during freshers week in United Kingdom on November 28, 2007. (Photo by Matthew Horwood/Alamy Stock Photo)

Residents recently returning to their area cleared by government troops react as they ride a tricycle a day after President Rodrigo Duterte declared the liberation of Marawi city in southern Philippines Wednesday, October 18, 2017. Sporadic explosions continue Wednesday as Philippine soldiers fought to gain control of the last pocket of Marawi controlled by Islamic militants. (Photo by Bullit Marquez/AP Photo)

A woman wearing a face mask and a child sit between rail tracks, during the imposition of large-scale social restrictions by the government to prevent the spread of the coronavirus disease (COVID-19) in Jakarta, Indonesia, April 12, 2020. (Photo by Willy Kurniawan/Reuters)

Erica Daly, a District Nurse Team Leader at Mersey Care NHS, stands in front of the “Liver Bird Wings”, an artwork by Paul Curtis on a wall within Liverpool's Baltic Triangle on April 29, 2020. (Photo by Peter Byrne/PA Images via Getty Images)

Iranians wearing face masks against the Covid-19 coronavirus attends Laylat al-Qadr prayers, one of the holiest nights during the Muslim fasting month of Ramadan, outside a mosque in the Tehran, on May 13, 2020. (Photo by Atta Kenare/AFP Photo)

A girl walks along rice paddy fields during “National Paddy Day”, which marks the start of the annual rice planting season, in Tokha village on the outskirts of Kathmandu on June 29, 2020. Splashing mud and drinking local rice beer, Nepali farmers this week celebrated National Paddy Day to mark the beginning of the rice-planting season, despite some coronavirus lockdown measures still in place. Traditional farming songs and laughter echoed in the air as farmers waded into waterlogged fields to sow green paddy. (Photo by Prakash Mathema/AFP Photo)