[Allahabad, India; December 21. Image via Getty.]

A young girl smiles at the photographer as her unseen mother sorts dried cow dung cakes in the Teliarganj area on the outskirts of Allahabad on December 21, 2009. Cow dung cakes are a major source of domestic fuel for rural households and an environment friendly alternative to firewood in the village areas in many parts of India. In recent times, dung is collected and used as biogas which is used to generate electricity and heat. The gas is a rich source of methane and is used in rural areas of India to provide a renewable, stable and environment friendly source of electricity. AFP PHOTO/Diptendu DUTTA
(Photo credit should read DIPTENDU DUTTA/AFP/Getty Images)