Cooking stove helps fight Himalayas glacial melt
24 September 2013 Last updated at 00:36 BST
Scientists have discovered that smoke from cooking stoves and dirty engines is causing glaciers to melt faster.
The glaciers are already under pressure from climate change. The smoke also deposits black soot on to the glaciers, which makes them absorb more heat.
A project in India, partly funded by British aid, is trying to get families to swap their traditional mud cookers for cleaner cookers - but they are more expensive and some families cannot afford them.
Roger Harrabin travelled to Tanda, a village in northern India, to see the effects of the old cookers, and find out how the new stoves work.