Around 13 megacities have so far been identified as ABC hotpots. Bangkok, Beijing, Cairo, Dhaka, Karachi, Kolkata, Lagos, Mumbai, New Delhi, Seoul, Shanghai, Shenzhen and Tehran where soot levels are 10 per cent of the total mass of all human-made particles. ABCs can reduce sunlight hitting the Earth's surface in two ways.
The haze, or an atmospheric brown cloud hanging over major Asian cities including Delhi and Mumbai, essentially affects local conditions and can be swept away by a new weather system or winter rains as is often the case in the Capital.
One of the most serious problems resulting from the brown haze that envelopes vast areas of Asia, the Middle East, southern Africa and the Amazon Basin, is the retreat of the glaciers in the Himalayas and Hindu Kush and in Tibet, according to lead researcher Veerabhadran Ramanathan, a professor of climate and ocean sciences at the University of California in San Diego.
The long-term hazards of the haze, or brown cloud, which forms over north Indian cities in winter are not yet well understood, though its adverse impact on health of the people is clear, a leading Indian expert said.
New York,
Asian cities from New Delhi to Beijing are getting darker, glaciers on the mighty Himalayas are melting faster and weather system is getting more extreme, a United Nations study has warned.
