Since being established in 2005, MARPOL Annex VI has gone through consistent change. Back at its inception, there were only Sulfur Emission Control Areas (SECAs), not Emission Control Areas – and those areas were purely monitored for sulfur oxide emissions (SOx), with no restrictions on nitrogen oxide (NOx) and particulate matter (PM) emissions.Successive changes in requirementsIn 2010, the International Maritime Organization (IMO) updated those laws to guarantee that ECAs monitored the...