By Michael Winship

Have you heard about the great brown cloud? No, it’s not a new nickname for Donald Trump (his cloud is more an intergalactic nimbus of Aqua Velva and Tang), or the ominous menace in a new Stephen King novel. It’s almost as nasty, though.

The Atmospheric Brown Cloud, formerly known as the Asian Brown Cloud, is a mass of air pollution hovering over northern India along the southern Himalayas and down across Bangladesh and the Bay of Bengal. The cloud began growing shortly after World War II, a smoggy mass of soot and sulfates from diesel emissions, wood fires and other burning stuff that’s almost two miles thick.

A new study by scientists from a number of research organizations – including the National Oceanic and Atmospheric Administration (NOAA) and the Scripps Institution of Oceanography – finds that the cloud’s pollutants are making cyclones in the Arabian Sea more intense.