It's prolly good that it didn't rain. All the chlorine would have dumped itself all over the place and killed all the fish.

This way it will have some time to dilute itself and disperse, some place else. For now, the clouds absorbed the gas, and the wind will hopefully move along the hazard. Watch out for an ecological disaster further down-wind, though. Best to keep it airborne as long as possible.

Also chlorine is toxic to bio-critters, including viruses. so that's a blessing in disguise, I guess. Perhaps the aim was to deprive self-sufficient fishermen.