https://phys.org/news/2018-05-quake-blackened-air-nepal-brick.html

While much work remains to be done in improving working conditions, an environmental initiative has already managed to reduce emissions from the kilns and efforts are now focusing on rolling out the programme across the region, with significant implications for tackling climate change.

There are more than 150,000 kilns in India, Bangladesh, Pakistan and Nepal belching out thousands of tonnes of soot—known as black carbon—a major air pollutant and the second largest contributor to global warming after carbon dioxide.