This mission is only available after choosing Sabal as the leader of the Golden Path and completing Cease and Desist . As you’re talking with Sabal about Amita, you find out that Utkarsh is being hit by artillery, so Sabal sends you to Utkarsh. You’ll have to hurry, as there’s a meter at the top of the screen that indicates how much time you have before you will fail.
On the way, you’ll likely encounter some enemies on the road, but it’s best to just blow right past them and not worry about killing them. Once you make it to Utkarsh, the meter at the top will disappear. Go to the marked house and talk to one of the civilians at the window, which will trigger the next part to start. You’ll now have to fend off waves of enemies that will attack the town.
There will be at least two Heavies in the first wave of enemies, as well as a bunch of other enemies. Once enough time passes, Sabal will warn you that artillery fire is incoming and for you to take cover. That’s your cue to quickly run to one of the marked points and hide, while the town gets bombed. When it’s over, crawl out of the hole and get ready to do it again.
As Sabal points out, his team has taken out one of the artillery cannons, but there’s two more. That means that there will be two more waves of enemies, with a round of artillery fire coming during the wave of enemies. As soon as you see the warning about the artillery coming in, ignore the enemies and hide. The mission will end after the third artillery strike.