Great article from nyt, lots of video and images that really making a damning case. Here's the link. https://www.nytimes.com/interactive/...-tear-gas.html
The main points.
1) police throwing tear gas from up high "“This is ridiculous,†said Jim Bueermann, former president of the Police Foundation in Washington, referring to a video that appeared to show tear gas being fired off a commercial tower....You are now taking a less-lethal tool, the tear gas, and making it a potentially lethal object.â€
2) shows the police firing in Kwai Fong one round, then another. Condemnation from the same Bueermann and from S. African expert.
3) firing tear gas at people "“They are being fired at very high velocity; the launchers that are used are basically guns†said Anna Feigenbaum, an expert on tear gas at Bournemouth University in England."
4) indiscriminate use of tear gas "The use of a second and third round of tear gas, to the experts, also seemed to go too far. “If people are leaving, and that was your intent, then stop using it,†Mr. Bueermann said."