International Maritime Organization’s 2020 regulation is continuing to make an impact

Researchers at the UK’s National Centre for Atmospheric Science found that the average sulfur content in ship fuel dropped nearly tenfold in open ocean areas after the International Maritime Organization’s 2020 regulation, which limits sulfur content in marine fuel at 0.5%. Prior to the change, many ships exceeded the previous 3.5 percent limit.

After 2020, it's reported that only a few ships were found to breach the new limit.

From the journal: Environmental Science: Atmospheres