Tokyo, September 29th 2011
From August 23rd to September 8th, the Ministry of Education reports that, following a survey on the spread of radiation throughout Eastern Japan, a helicopter measured airborne Cesium contamination over the Gunma prefecture and published a map on how it has spread. It is now clear that the contamination has scattered way beyond 250km from Daiichi in the North and West, amidst previous reports (or lack of, in this case) from TEPCO. Mountains such as Kiryu City, which is located 180 km away from Daiichi, recorded 10,000 to 30,000 Bq. Some parts in Nagano exceed 30,000 Bq more than 250 km away.
As to the South (Tokyo, Saitama and Chiba) is still anyone’s guess on how bad it could be. Read more on this story on Asahi (in Japanese)