Definitely CGI. Notice that the white spots are falling more like snow over an area that looks to be a mile or so square. WP disperses over perhaps a couple hundred yards or meters.

And usually even the aerial burst devices shower downward like an umbrella but with a lot of dense white smoke which would hide such things as ships or a group of tanks. Obviously individual particles would also have thick smoke trails - completely absent in the subject video. It's a fake, no doubt about it.