Chile's greenest town? What Finland can learn from La Pintana

Nationally, only about a third of municipal solid waste is recycled. An initiative to use simpler, standardized signs and labels is helping communities reap greater benefits from recycling.

Most cities may have enacted smoking laws to curb people from lighting up in public, but cigarette butts continue to blanket streets, parks and beaches. Salem, Mass., and New Orleans are two such communities that have partnered with TerraCycle, a New Jersey-based company that pays by the pound for cigarette waste.

Food waste costs billions of dollars a year and is a significant contributor to greenhouse gas emissions. French government just passed a law banning grocery stores from destroying or throwing away unsold food, and instead directing it to those in need.

America loses about 31 percent of its food to waste. Driven by environmental, social and economic pressure, more and more cities are starting mandatory compost programs.

Lack of access to sanitary bathrooms in the village of Kivalina, Alaska led to the implementation of a novel, home-based water sanitation system, currently being tested for effectiveness. The hope is that it proves to be a solution for areas all over the state with lack of access to clean water systems.

Throughout India, wastepickers – people who scour landfills for garbage they can sell to recyclers – live at the bottom of society. But the city of Pune did something radical: with the help of a collective, they did away with expensive garbage trucks, and now all household garbage is collected by wastepickers with pushcarts. Pune saves millions of dollars each year and recycles more – and the wastepickers have decent wages and social standing. The concept is now spreading globally.

The government wants more farmers turning waste methane into biogas to help combat the negative effects of global climate change. California is leading the initiative, largely through a cap-and-trade program.

Mysuru has become a gleaming example for solutions to India's vaster struggles with solid-waste management, toilet construction, sanitation strategy, public outreach, and other measures. The city uses a decentralized model that leverages a mix of municipal resources, NGO leadership, civil society, and cooperation from proud residents and businesses.

The United Kingdom is finding creative ways to simultaneously address renewable energy needs and waste disposal. Combined Heat and Power (CHP) plants are utilizing chicken manure from farms and coffee grounds to create electricity. The initiatives have the added benefit of improving standards for the treatment of poultry, as well as reducing the distribution of harmful toxins from the waste.

The amount of plastic debris in our oceans and water sources - especially nanoplastics that are increasingly prevalent in our food chain - is so enormous it's often beyond comprehension, and immensely difficult to address. As countries continue to industrialize and single-use products become more commonplace, the flow of harmful plastics into the environment seems insurmountable. But a number of clever inventions and dedicated individuals are working to help get plastics out of our water - and more importantly - encourage practices to reduce, reuse, and recycle.