The world’s worst nuclear reactor mishap in 25 years was caused by a massive natural calamity but compounded by what appear to be surprising mistakes by Japanese engineers. The result has been a fast-moving disaster that has left officials careening from one emergency to the next.

The disaster at the Fukushima-Daiichi nuclear power plant has highlighted the importance of nuclear energy to Japan and the power long wielded by the nuclear sector. But that influence now is sure to wane, to the relief of opponents who have fought for years to check nuclear's rapid growth.

For decades, deadly outbreaks of cholera were attributed to the spread of disease through poor sanitation. But recent research demonstrates how closely cholera is tied to environmental and hydrological factors and to weather patterns — all of which may lead to more frequent cholera outbreaks as the world warms.

For years, a chemical plant in the Chinese village of Qiugang had polluted the river, poisoned the drinking water, and fouled the air — until residents decided to take a stand. The Warriors of Qiugang, a Yale Environment 360 video co-produced by Ruby Yang and Thomas Lennon, tells the story of the villagers’ determined efforts to stop the pollution.

With high gold prices fueling a global gold rush, millions of people in the developing world are turning to small-scale gold mining. In many countries, including Colombia, miners are putting themselves and those who live nearby at risk by using highly toxic mercury in the refining process.

The synthetic chemical, BPA — found in everything from plastic bottles to cash register receipts — is a potent, estrogen-mimicking compound. In an interview with Yale Environment 360, biologist Frederick vom Saal harshly criticizes U.S. corporations and government regulators for covering up — or ignoring — the many health risks of BPA.

The sludge spill in Hungary dominated world news for days, as horrific images of red-mud rivers appeared nonstop on the Internet, newspaper front pages, and TV screens. Yet other environmental threats — less visible, but potentially more devastating — often go largely unnoticed.

LEED certification has emerged as the green standard of approval for new buildings in the United States. But the criteria used for determining the ratings largely ignore factors relating to human health, particularly the use of potentially toxic building materials.

While some studies have suggested that frequent use of cell phones causes increased risk of brain and mouth cancers, others have found no such links. But since cell phones are relatively new and brain cancers grow slowly, many experts are now recommending taking steps to reduce exposure.

Insecticides such as DDT have long been used to combat the scourge of malaria in the developing world. But with the disease parasite becoming increasingly adept at resisting the chemical onslaught, some countries are achieving striking success by eliminating the environmental conditions that give rise to malarial mosquitoes.

Hydro fracturing is a profitable method of natural gas extraction that uses large quantities of water and chemicals to free gas from underground rock formations. But New York City’s concerns that the practice would threaten its water supply have slowed a juggernaut that has been sweeping across parts of the northeastern United States.

As humans increasingly encroach on forested lands and as temperatures rise, the transmission of disease from animals and insects to people is growing. Now a new field, known as “conservation medicine,” is exploring how ecosystem disturbance and changing interactions between wildlife and humans can lead to the spread of new pathogens.

In the last few decades, urban sprawl, once regarded as largely a U.S. phenomenon, has spread across Europe. Now an emerging group of planners is promoting a new kind of development — mixed-use, low-carbon communities that are pedestrian-friendly and mass-transit-oriented.

After decades of living with fouled rivers and filthy air, residents of China’s Manganese Triangle are rising up and refusing to accept the intolerable conditions created by illegal mining activity. Their bold protests have shone light on the dark side of China’s economic boom. From Sichuan province, Chinese journalists Zhou Jigang and Zhu Chuhua report.

U.S. cities have been using green planning to spark economic development, helping create a real urban renaissance in America. With a new administration soon to arrive in Washington, these same approaches may finally start being used on a national scale.