Councilmember Reakash says when you get this quest, "And finally, you must take the jar of the Windspirit and pass it through the mists of the of either of the waterfalls in the Grove. It will collect the mists I seek."
Not only is this bad English, the waterfalls in the Grove will not fill your jar... You have to fill it at the waterfalls in the Hollow, as some have already said. Hooray for SOE
-Niluna