Throughout the developing world, women walk miles every day to gather firewood. As nearby forests are depleted, women are forced to walk farther and farther or to buy expensive cooking fuel. Burning wood for fuel also forces women to inhale dangerous amounts of smoke, and pollutes the atmosphere, releasing large amounts of carbon dioxide that contributes to global warming. Meanwhile, another source of fuel, cow dung, lies exposed and unused, leaking more greenhouse gases into the atmosphere.
Biogas systems convert cow manure into clean-burning cooking fuel. The manure from four cows produces enough fuel to satisfy the needs of a family. The Bajaj Foundation has constructed over 600 biogas units since 2009, transforming the daily lives of hundreds of families and contributing to the global fight against greenhouse gases. By capturing and using the gas produced by cow manure, biogas systems free women from the need to gather firewood, eliminate the harmful smoke associated with cooking, and help reduce greenhouse gases.
Gandhi believed in sustainability. Look at the farm he helped found in South Africa, Tolstoy Farm. Over a thousand acres, Tolstoy Farm boasted hundreds of fruit trees that produced almonds, walnuts, apricots, peaches, and figs. The farm was a model of sustainability. Water was transported manually from a nearby spring. Wastewater was gathered in buckets and used to water the trees. A compost system turned food waste into fertile manure. Human waste was also transformed into manure. Residents made their own sandals. It was, in Gandhi's words, "a busy hive of industry."
Gandhi's thoughts on Tolstoy Farm are available at here. Search for "Tolstoy Farm." Or explore other examples of Gandhi's writings on sustainability.