Recycling

Eric Lombardi, a waste-management guru, has drawn up a fanciful plan for an "eco-cycle, zero waste park" which reimagines the dump as a composting, recycling, and educating facility.

As the worst recycler amongst the 30 largest American cities, Houston has a lot of trash on its hands. But many obstacles stand in the way of the city closing the loop.

With 70 percent of its waste already diverted from landfills, San Francisco continues to push forward with new laws and programs to increase recycling.

Plans to redevelop Asia's largest slum will displace over 1 million people, many of whom earn their livelihood recycling Mumbai's trash.