Cuts in sulfur emissions from oceangoing vessels have been tied to a reduction in lightning stroke density along heavily trafficked shipping routes in the Bay of Bengal and the South China Sea, according to new research from the University of Kansas.

The work is published in the journal npj Climate and Atmospheric Science.

Previous studies had found frequent lightning along shipping routes over the Bay of Bengal before a 2020 International Maritime Organization rule capped sulfur in fuel used by oceangoing ships, leading to a roughly 70% drop in sulfate emissions in the Bay of Bengal.