From Paris to Hong Kong, tear gas has become a common sight on city streets across the globe.
Law enforcement insists it is a vital tool to keep the peace, but there are growing demands from campaign groups and some medical professionals to reign in its use.
"In terms of how you would acutely feel when you get attacked by tear gas, most people would feel an intense burning," Professor Peter Chin-Hong of the University of California told Euronews.
"It's going to go down your airways and your lungs may react, so you may have a bronchospasm, you may feel like you have an asthma attack in some people," he said.
Black Lives Matter protests have once again brought the issue to the forefront of global conversation with chemical agents being deployed on both sides of the Atlantic to control crowds.
"Tear gas is often presented as a non-lethal or 'less lethal' weapon, which allows law enforcement to use it...to push back, for example, violent crowds," Nicolas Kramayer from Amnesty International told Euronews.
Watch in full: Culture Clash: The truth about tear gas
"What we have observed...through an investigation we carried out in 22 countries using 500 videos.. is that very often tear gas is used in a way that is either abusive, arbitrary or in some cases punitive. That's to say tear gas is used to inflict pain on peaceful people," he said.
Steve Maia Canico, 24, drowned trying to escape tear gas at the Fete de la Musique in Nantes in June 2019. Silent protests marked the anniversary of his death. The officer in charge was later demoted following an inquiry, but this did little to quell anger. French police did not respond to requests for comment.
"Amnesty International is now asking for a total ban on the use of tear gas," Kramayer said.
"Nevertheless, it's essential that beyond the pure necessity there is also the opportunity to ask yourself... 'if I'm going to throw tear gas for a few protestors, am I taking the risk of inflicting tear gas on thousands of peaceful protestors?'"