It's a wonder gadget. It safeguards eyes and lungs.
It protects glaciers from melting. It saves forests. This miracle device is... a cooker.
In many traditional societies, cooking and fuel collection remains a woman's responsibility. And the black smoke from these stoves is wrecking the health of millions of people each year.
It's only more recently acknowledged that the black smoke from the stoves is also heating the atmosphere and contributing to the decline of glaciers.
Sooty particles from the open fires drift up to mountains where they settle on gleaming white ice, making it darker and more prone to absorbing heat from the Sun.
A recent paper concluded that soot from Europe's industrial revolution could have shrunk Alpine glaciers.
The same is happening now in the Himalayas where the glaciers supply tens of millions of people with meltwater which keeps rivers flowing during the dry season.
A remedy that tackles both problems is a new-style cooker which reduces smoke by 80%. It also needs only half as much wood fuel, which reduces the strain on forests and saves people time.
The mini marvel we witnessed in blazing action at Tanda in the North Indian state of Uttar Pradesh is a twin stainless steel cylinder resembling a small bathroom pedal bin. The heat is controlled with remarkable precision by a battery-powered fan beneath.
The local shop-keeper has bought the stove for his four daughters who do the cooking in the family. One, Sonali Maurya, tells me they're delighted because the old mud stove sometimes made the kitchen unpleasantly hot, turned the pots black and making her sisters cough.
You can see how the smoke and heat have charred and blackened the beams of the kitchen lean-to.
The cooker, designed by a Delhi research institute, Teri, cost about £40 under a scheme supported by UK taxpayers' aid. The design has also also been made open-source. But the alliance keeps a catalogue of other clean cook stoves.
The task is to get models like it to the estimated 2.5 billion people worldwide that currently rely on mud stoves.
The glacier connection might help raise the necessary cash. Western governments are struggling to cut the CO2 emissions that have heated the planet.
It's much easier to tackle the more contained warming created by black smoke from cooking stoves.
We took a rocky road to visit Batal glacier, north-west of Tanda to see how the ice is shrinking. The effects of black smoke are so subtle that they're invisible to the eye.
There's great uncertainty about exactly how much damage is caused by climate change and how much by the black smoke.
But the latest report from the Intergovernmental Panel on Climate Change (IPCC) this week, will accept a growing body of evidence that the smoke from stoves, diesel engines and crop burning does indeed warm glaciers.
The Global Alliance for Clean Cookstoves aims to bind the US and developing countries in an enterprise of mutual interest to promote the uptake of clean cookers. But progress has been slow.
Unlike the CO2 emissions that are warming the planet and shrinking the glaciers, black carbon is a problem that is contained, with a comparatively straightforward solution – if there’s the will to do it.
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