these warnings were not issued for tokyo which is 200+kms from the plant.
these warnings were given to those within 30km of the nuclear plant.
http://www.washingtonpost.com/world/residents-warned-to-stay-inside-after-catastrophic-radiation-leak-at-japanese-nuclear-plant/2011/03/15/ABPDEVW_story.html
since radiation cannot penetrate walls or windows.
the government also suggested to cover your mouth and nose with a wet cloth if you want to go outside.
30 km radius evacuated now....
I edited my original message with a quote from the Globe and Mail which quotes an Japanese government official.
Common sense would dictate explosions at nuclear power plants are not a favourable thing.
so you believe the japanese official line of the explosion REDUCING radiation levels?
http://www.theglobeandmail.com/news/world/asia-pacific/japan-launches-rescue-operation-braces-for-possible-nuclear-meltdown/article1939779/