It ain't easy being green in the world's most polluted city

As India's government promotes organic exports, farmers in Punjab have non-economic reasons for avoiding pesticides: Their health.

In developing countries, environmentally friendly and practicality don't always go hand-in-hand. Biogas are changing that. With biogas technology, methane is derived from the feces of humans and animals and is used in place of traditional fuel which improves sanitation across these regions and is a benefit for the environment.

Across the world, 1.8 billion people have to make a daily decision between either drinking unsafe water or paying exorbitant prices for bottled water. I-Drop Water, a company that has devised purification systems that can be installed at affordable rates in local grocery stores, is working to solve this problem by bringing accessible purified water to people throughout Africa.

Burlington, Vermont counts itself as America's first all-renewable city, satisfying its energy needs through a combination of sustainably harvested pine and timber wood chips, hydroelectricity, four wind turbines, and a solar panel array near the local airport. Aside from the environmental benefit of renewable energy, the city has seen other benefits in the form of cheaper energy costs and healthy, locally-grown food.

The Network of Water Rights Initiative (NWRI) works with local organizations to improve access to safe water through education and awareness campaigns aimed at enlightening people about the health risks of contaminated water. NWRI has led water clean-up efforts, helped locals establish security measures to prevent people from dumping waste in water and even helped get a water bill signed into law that would improve water supply and sanitation services across the state.

Members of a water-insecure community mobilized to contribute a portion of their monthly stipends to repair and maintain the singular borehole providing water to the village. The community members — primarily women — also installed water taps throughout the community in locations like schools and mosques to ensure easy access to clean, safe drinking water.

To combat health and sanitary issues arising from high rates of open defecation and a lack of government support, community members worked together to fund and build 14 easily accessible toilets that are cleaned daily and open for anyone to use.

San Francisco-based New Resource Bank was launched with environmental sustainability lending as its niche. But it pursued easier profits for a time, risking its survival and mission until a new CEO turned its fortunes around with a laser focus on the original mission, bolstered by learning its borrowers' businesses intimately. The bank doubled in size and merged with a larger bank, making itself a model for mission-driven lending in such businesses as solar, wind energy, and organic foods – and by attracting institutional depositors and investors as interested in social change as they are in profits.

A community-based water testing and lead-education pilot program aimed to rebuild confidence and trust among Flint residents, who are skeptical of state-affiliated testing. Trained students collected water samples that were tested by University of Michigan labs. Educational materials provided with results included how to install, maintain, and use filters. While most samples didn't show issues, households with dangerous lead levels were given bottled water, filters, and other services. Once the pilot ended, the Mckenzie Patrice-Croom Water Lab secured funding to continue free community-based water testing.

BlueConduit, an analytics startup, applies statistical models to identify neighborhoods and households that might have lead pipes. The models include dozens of factors, such as the age of the home and proximity of other homes where lead has been found, to help predict likely locations of lead pipes and create a ranking by likelihood that cities can use to prioritize which pipes to examine. In Flint, MI, about 70% of the homes identified using the models had lead pipes, compared to about 15% of homes where excavations did not use the model. The company is working with organizations in dozens of other cities.