BEIJING - Thick brown clouds of soot, particles and chemicals stretching from the Persian Gulf to Asia threaten health and food supplies in the world, the UN reports.
The regional haze, known as atmospheric brown clouds, contributes to glacial melting, reduces sunlight and helps create extreme weather conditions said a report commissioned by the UN Environment Program.
The huge plumes have darkened 13 megacities in Asia -- including Beijing, Shanghai, Bangkok, Cairo, Mumbai and New Delhi -- sharply dimming the amount of light by as much as 25 per cent in some places.
Caused by the burning of fossil fuels, wood and plants, the brown clouds also play a significant role in exacerbating the effects of greenhouse gases in warming up the Earth's atmosphere, the report said.
Some particles within the pollution cloud, such as soot, absorb sunlight and heat the air.
That has led to a steady melting of the Himalayan glaciers, which are the source of most of the major rivers on the continent, the report said.
