Chinese dissident artist Ai Weiwei was detained at Beijing airport while attempting to board a flight to Hong Kong on April 3. The artist's wife, assistants, friends, family members and associates were also subsequently detained and interrogated. But Ai himself continues to be held at unknown location. China's Foreign Ministry said only that he is being investigated for unspecified "economic crimes" and that his detention has "nothing to do with human rights or freedom of expression." The detention has nonetheless sparked global protests. In London, supporters gathered at the Tate Modern museum on April 11, and climbed into Ai's "Sunflower Seeds" installation—an exhibit of 136 tons of hand-painted porcelain sunflower seeds—and scattered posters bearing the message: "Free Ai Weiwei." (CBC, April 11)

Japan raised the severity level of its nuclear crisis to seven on April 12—putting it on par with the Chernobyl disaster—as stricken reactors at the Fukushima Dai-ichi complex continue to release large amounts of radioactive substances. The Nuclear Industry and Safety Agency (NISA) had previously assessed the crisis at at level five, the same as the Three Mile Island accident in the United States in 1979. The move came as engineers were fighting another fire at reactor Number 4, and as a 6.3 aftershock centered off the coast of Chiba rocked eastern Japan. (Brisbane Times, April 12; Reuters, April 11)

A magnitude 7.4 aftershock hit northeastern Japan April 7—raising fears of a deepening of the crisis at the stricken Fukushima nuclear plant. Tokyo Electric Power Co. (TEPCO) reported no serious incidents as a result of the aftershock. But Ed Lyman, a nuclear safety expert at the Union of Concerned Scientists told the LA Times' Ecocentric blog: "The damage that has been done to date by the earthquake and tsunami has degraded the plant's ability to withstand ground motion, so you have more chance of a containment breach with the next earthquake. The conditions at the plant are so fragile, it can't really stand many more challenges."

A second attempt to stop radioactive water leaking into the Pacific ocean at the Fukushima nuclear plant by using paper and sawdust bound with a chemical compound failed April 4. Engineers are now resorting to a third plan: building mounds of silt around the reactor to filter radioactive particles. (Daily Mail, April 4) Officials in Fukushima prefecture have launched an emergency program to measure radiation levels in school playgrounds. More than 1,400 schools and nurseries will be tested over two days amid growing anxiety among local parents. Officials say there should be no risk to children if they stay outside a 30-kilometer evacuation zone. (BBC News, April 4) Efforts to protect Tokyo’s water supply from radiation have led to a run on Indonesian coconut husks. Granulated charcoal made of the husks is used in Tokyo area treatment plants. Prices for the absorbent carbon material have jumped 44% since the disaster started. (Bloomberg, April 4)

From the central committee of the Movement for Democratic Socialism (MDS), Tokyo, March 27:

Let us struggle for democratic reconstruction of eastern Japan, and for the total abolishment of nuclear power plants!
More than two weeks have passed since March 11th gigantic earthquake that hit eastern Japan. The death toll is increasing even now, reaching almost thirty thousand to include those who are still unknown whether safe or not. MDS extends our deepest condolences to all the victims in this disaster. Particularly, Fukushima Daiichi nuclear power plant poses a serious issue as it continues to deteriorate its radioactive contamination. In Fukushima as well as in neighboring prefectures, shipments of vegetables and raw milk have been suspended since higher level of radioactive substance was detected from them. Tap water contaminated by radioactive iodine has expanded to encompass the Tokyo Metropolitan area.

South Korean environmental activists staged an anti-nuclear rally on March 28, marking the 32nd anniversary of the Three Mile Island nuclear accident in Pennsylvania. Dozens of protesters wearing white masks gathered in downtown Seoul and denounced their government's nuclear development plans. Said protest leader Kim Hae-jung: "Today is the 32nd anniversary of the Three Mile Island nuclear plant accident, and it's been 17 days since the nuclear tragedy broke out in Japan. We're here to urge our government to change its plan to expand nuclear plants and to inform people of the danger of nuclear plants." South Korea has 21 nuclear power plants, with seven more under construction, and another 11 planned. (NTD-TV, March 28)

Tokyo Electric Power Co. (TEPCO), operator of Japan's stricken Fukushima Dai-ichi nuclear plant, said April 2 that highly radioactive water is leaking directly into the ocean, which may help explain high levels of radioactivity in seawater off the coast. The water is coming from an 8-inch (20-centimeter) crack that was found in the concrete pit holding power cables near reactor Number 2, with the radiation level measured at 1,000 milli-sieverts an hour. The annual limit of radiation exposure allowed for Fukushima workers is 250 milli-sieverts. Efforts to seal the crack by pumping in concrete have failed to slow the flow of water into the ocean. TEPCO officials said they will next try using a polymer—a type of quick-setting plastic. The tainted water is pooled up some 10 to 20 centimeters high at the bottom of the pit. (LAT, Kyodo News, April 2)

Seawater near Japan's stricken Fukushima Dai-ichi nuclear power plant shows significantly higher levels of radioactive iodine than in recent days, Japan's nuclear safety agency reported March 30. Hidehiko Nishiyama, deputy director general of the Nuclear and Industrial Safety Agency, said that seawater collected about 300 yards from the Fukushima Dai-ichi plant was found to contain iodine 131 at 3,355 times the safety standard, the highest levels reported so far. Meanwhile, Tokyo Electric Power Co. (TEPCO), operator of the plant, acknowledged for the first time that at least reactors 1 through 4 of the six-reactor complex will have to be written off. (NYT, March 31) A US engineer who helped install reactors at Fukushima, speaking anonymously to the Scandinavian environmental NGO Bellona, said he believes the radioactive core in reactor Number 2 may have melted through the bottom of its containment vessel and on to a concrete floor—a development that would pose a grave risk to soil and groundwater. (Bellona, March 31)