That's according to the Ministry of Economy, Trade and Industry (METI), which continues to be in charge of regulating the nuclear industry because the new and (supposedly) improved Nuclear Regulatory Agency under the Ministry of the Environment is still nowhere to be seen or heard (and likely not to be seen or heard for a very long time, as things are going at this time).
Looking at the radiation map that the Ministry published on April 23, 2012, part of Namie-machi, Iitate-mura, Okuma-machi, and Futaba-machi will continue to be more than 20 millisieverts per year external radiation. They are basically the same areas that are in red in the map as of March 2012 (100 millisieverts per year and higher).
Also note that the air radiation levels in most of Date City and Fukushima City will still be more than 1 millisievert per year 20 years from now.
In the information blackout (natural and intentional) right after the March 11, 2011 earthquake/tsunami/nuclear accident, people inside the 3 kilometer radius from the plant, then 5, 10, 20 kilometer radius, fled in the direction of the red area in the map along Route 114 to Namie-machi. Some then took Route 399 to Iitate-mura and then to Date City, others through Kawamata-machi on their way to Fukushima City.
As the mayor of Namie-machi said in the investigation committee set up by the Diet, people were irradiated unnecessarily because the government didn't say a thing about radiation (other than of course, "no immediate effect on health").
The METI simulation maps on air radiation levels in the areas in and around the evacuation zones in Fukushima, based on the aerial surveys done in November 2011 (labels for municipalities are mine):
Air radiation levels as of March 2012:
As of March 2013:
As of March 2022:
As of March 2032: