India, Feb. 12 -- For about a year, 10,000 residents of the BARC Cooperative Housing Society in Anushakti Nagar have taken pride in being a "zero-waste society". A workforce of 40 women manages the 300 kg of waste produced by the society every day, reducing the burden on Mumbai's overwhelmed landfills.

But that's not all. The women, trained by the NGO Stree Mukti Sangathana, manage the waste through composting pits and four to five biogas plants that generate enough energy to power a canteen run by the housing society.

How did they achieve this? It took some tweaks at the waste-collection stage. In this housing society, door-to-door waste collection is handled by a separate set of contractors who coordinate with the women operating the ...