Asian brown cloud

The Asian Brown Cloud is an enormous three kilometre thick layer of haze[?] covering the northern Indian Ocean, India, Pakistan, and much of South Asia, Southeast Asia, and China. It is created by a range of airborne particles and pollutants, characteristic of biomass burning and industrial emissions. The cloud can last for up to four months, most commonly in the winter (December to April). the haze is toxic in itself and has an adverse impact on rainfall and sunlight.

It was properly defined and measured by the UNEP (United Nations Environment Programme) INODEX (Indian Ocean Experiment) running from 1995.