During the dry winter season from October until May every year, the heavily populated Indo-Gangetic Plain is plagued by severe air pollution. In recent years, people in India and Nepal have suffered from periods of suffocating air pollution, known scientifically as Atmospheric Brown Cloud (ABCs).
In 2015 India’s air pollution levels overtook China’s. According to an analysis by Greenpeace of NASA satellite data, the average particulate matter exposure in India exceeded that of China’s, and more importantly China’s exposure fell 15% between 2014 and 2015, while India’s was increasing by 2% per year.
Pollution is worse in the winter because there is no rain to wash pollutants from the air. In Kathmandu, for example, days with clear views of the Himalayas become very rare due to the heavy brown clouds shrouding the valley. Emissions from burning fossil fuels and biomass for cooking and heating build up during the dry season when brown clouds extend from the Indian Ocean to the Himalayan ridge.
The soot, sulphates and other harmful aerosols in Atmospheric Brown Clouds pose a major threat to the water and food security of Asia, according to a 2008 study by UNEP. The soot settles on the glaciers, darkening the snow and increasing absorption of energy. This speeds up the melting of glaciers and snow pack in the Hindu Kush-Himalayas – which provide water for million of people living downstream.
Pollutants also absorb the sun and heat the atmosphere. They are as “important as greenhouse gas warming in accounting for the anomalously large warming trend observed in the elevated regions,” states the report.
With the westerlies blowing across the Indo Gangetic plain, pollutants spread across Nepal and climb up valleys and slopes of the Himalayan ranges, extending up to Tibet.
Ice-core samples taken from both the southern and northern slopes of the Himalayas have also revealed rising soot concentrations during times of rapid industrialization in recent decades, indicating pollution could travel over the high mountain range.
In recent years Chinese scientists have found more definitive evidence that the Himalayas do not block the passage of pollution into the central region of the Tibetan plateau. Thanks to observations at various observatory stations on the northern slopes of the Himalayas since 2009, they have found a similar concentration and type of pollutants on both the south and north sides of Mount Everest.
The world is one family, all of us share the same planet. Is it wishful thinking to hope that instead of scoring political points, all of us in South Asia start joining hands to save our glaciers from melting and our mountains from being suffocated with dirty brown clouds?