Through the lens

Berlin was in mourning this week after news broke that celebrated polar bear cub, Fritz, had passed away. It's still unclear what killed the bear but zoo director Andreas Knieriem said his liver was massively inflamed and enlarged, which is a sign of serious infection. Fritz was born in November last year in Tierpark Berlin to much fanfare. He was the first baby polar bear born at the zoo in 22 years and was set to make his public debut in March.

On Tuesday, poachers broke into a zoo near Paris and killed a rare white rhino for its horn. The intruders shot 4-year-old male, Vince, in the head three times and stole his main horn. The second horn was partially cut, leading zoo officials to suspect the assailants may have been scared off in the act or suffered an equipment failure. Investigators estimate the stolen horn to be worth between 30,000 and 40,000 euro ($31,700 to $42,250) on the black market. Pictured are Vince's enclosure-mates who were unharmed in the attack. 

The southern German city of Stuttgart is building moss-covered walls to fight its air pollution problem. Air quality has become so bad in the city that residents sued the mayor Fritz Kuhn and president of the Stuttgart administrative district Wolfgang Reimer. A court has ordered the state of Baden-Württemberg, of which Stuttgart is the capital, to deliver a plan to fix the problem. Some hope moss walls could help. Moss usually grows in mountain forests and moors and it can "eat up" air pollution. Pollutants cling to the moss's sticky surface and bacteria converts them into biomass. 

From Germany to Iran, air pollution is a global problem. Fine particulate matter has reached up to 66 times above the safe limit in the Ahwaz, a city in Iran's oil-rich province of Khuzestan. One resident described the problem to DW: "Within hours, there was dust everywhere. Suddenly, I had red spots on my whole body. My skin felt like it was on fire and I was hospitalized," said teacher Rosita. The country is suffering from a range of environmental problems but nobody is taking responsibility for them.On March 5, NASA captured this other-worldly green hue in the Antarctic Ocean. The color is caused by phytoplankton on the surface of the water. Phytoplankton are microscopic marine plants that flourish in the waters around Antarctica in the southern hemisphere's spring and summer, according to the U.S. space agency. If conditions are right, the plankton can grow in large enough quantities to make the green tinge visible from space.