Firewood, woody agrowaste Such as stalks of cotton and pigeonpea are burnt directly in domestic and large sized community wood burning cook stoves. A traditional rural cook stove, made of unfired clay, has a very low efficiency, it produces a lot of smoke and soot and it has a life of just a couple of years. The cook stoves developed by ARTI not only have a high efficiency of about 25% but they also reduce the indoor air pollution. ARTI has developed several models. Some of them are made of cement concrete, with the help of mould. Another model has been made of insulative bricks, whereas some others are metallic.