Complex sentence: In the Wanni jungles of Sri Lanka where the grid had been successfully applied, civilians and villages were few and far between, enabling heavy firepower like attack helicopters and artillery to be brought in to support troops in the grid in minutes.
Split into simpler sentences: In the Wanni jungles of Sri Lanka where the grid had been successfully applied, civilians and villages were few and far between, and so attack helicopters and artillery could be used. This enabled heavy firepower to be brought in to support troops in the grid in minutes.