This is one of the two missions in the second set where you have to choose between Amita and Sabal. Remember that choosing one over the other will lock you out of doing the latter’s mission.
As with the Balance of Power choice before, choosing Sabal over Amita will lock you out of being able to do Amita’s mission. Sabal wants you to destroy the opium fields at the tea factory, as he thinks turning Kyrat into a drug state is not the answer. You’re going to need something that can burn things, so pack up on Molotov Cocktails and head to your destination.
When you get there, forget about doing stealth and go straight in with guns blazing. However, there are two things you need to watch out for right away, one of which is a sniper on the main building and the other being the mortar that is close to the building. As for objectives, you have to destroy the stacks, as well as the opium fields.
The best thing to do initially would be to clear out the entire compound of enemies, letting you concentrate solely on destroying your objectives. There will be dogs coming after you as well, so keep an ear open for their barks. Once you’ve cleared out most of the enemies (it seems like more will continually appear), you can start going after the drugs.
The opium stacks are large, white stacks that will be glowing, and the game tells you that you have to burn them in order to destroy them. Sometimes, there will be an explosive canister or something similar near them, so use those. For the fields, it’s best to use your Molotovs, but make sure you shut off any sprinkler systems that have been activated. The mission will be over when you’ve destroyed everything.