At the beginning of the mission, while flying the chopper you want to use your machine gun and rockets to blow up as many explosive containers as possible. These can be found on the roofs of the various buildings and appear as large white tanks which explode when shot. There are easily over 100 of these in this section. Just take your time and make sure you shoot everything that looks explosive, while also taking care of the enemies so that you're not killed.
The achievement will unlock once 80 containers explode.