Complex sentence: In Asia, river piracy is a major threat, even in the present-day, particularly in the southeast, in a region, known as the "Golden Triangle", where drug trafficking of heroin is an international law enforcement problem.
Split into simpler sentences: In Asia, river piracy is a major threat, even to the present-day. Currently, in Southeast Asia, in a region known as the "Golden Triangle", illegal drug trafficking, of heroin is an major international law enforcement problem.