Children play dodge ball in a playroom at the Emporium kindergarten in Koriyama, west of the Fukushima Daiichi nuclear power plant. Since the tsunami that caused radiation to leak from a local nuclear power plant children aged 3 to 5 usually limit their time outdoors to 30 minutes or less per day. Toru Hanai / Reuters March 10, 2014
Five-year-old Atsunori Kaneta plays at his home in Koriyama, west of the tsunami-crippled Fukushima Daiichi nuclear power plant. An annual survey by the Fukushima prefecture board of education found that children in Fukushima weighed more than the national average in virtually every age group. The cause seems to be a lack of exercise and outdoor activity because of parents' fears concerning radiation. Toru Hanai/ Reuters. March 10, 2014
Four-year-old Iori Hiyama rides a tricycle at an indoor playground which was built for children because parents don't allow them to play outside because of concerns about nuclear radiation in Koriyama, west of the tsunami-crippled Fukushima Daiichi nuclear power plant. Toru Hanai / Reuters. March 10, 2014
A man uses a roller near a Geiger counter, during nuclear radiation decontamination work at a park in Koriyama, west of the tsunami-crippled Fukushima Daiichi nuclear power plant, Fukushima prefecture . It is three years since the tsunami led to radiation contamination in the area after a leak at the power plant.Toru Hanai / Reuters March 10, 2014.
Children bow to greet their nursery school teacher as they wait for a school bus heading to the Emporium kindergarten in Koriyama, west of the tsunami-crippled Fukushima Daiichi nuclear power plant in Japan.
A child walks past a geiger counter, measuring the background radiation level at Koriyama Station in Koriyama, west of the tsunami-crippled Fukushima Daiichi nuclear power plant. Toru Hanai / Reuters. March 10, 2014
A girl wearing a mask sits in a school bus heading to a kindergarten in Koriyama, west of the tsunami-crippled Fukushima Daiichi nuclear power plant, Fukushima prefecture. March 11 marks the third anniversary of the earthquake and tsunami that devastated Japan's Fukushima Daiichi nuclear power plant. Toru Hanai / Reuters
Koriyama city, a short drive from the crippled Fukushima nuclear plant, recommended time limits for young children to play outside after the disaster in 2011. The limits were lifted last year, but many kindergartens and nursery schools continue to obey them . Toru Hanai / Reuters March 10, 2014
A girl runs past a geiger counter, a familiar sight in Koriyama since the radiation leak at a nuclear power plant following the 2011 tsunami. Toru Hanai / Reuters March 10, 2014
Two-year-old Sakuya Zui plays at an indoor playground which was built for children and parents who refrain from playing outside because of concerns about nuclear radiation in Koriyama, after the radiation leak in 2011. Toru Hanai / Reuters. March 10, 2014
Two-year-old Nao Watanabe plays in a ball pit at the indoor playground at Koriyama, west of the tsunami-crippled Fukushima Daiichi nuclear power plant. Toru Hanai / Reuters
Children play at an indoor playground facility in Koriyama, west of the tsunami-crippled Fukushima Daiichi nuclear power plant, in Fukushima prefecture in Japan. Toru Hanai / Reuters. March 10, 2014
One-year-old Daichi Toyota plays with his mother at the indoor playground which was built for children and parents who refrain from playing outside because of concerns about nuclear radiation in Koriyama, west of the tsunami-crippled Fukushima Daiichi nuclear power plant. Toru Hanai / Reuters. March 10, 2014
Two-year-old Sakuya Zui plays at an indoor playground which was built because of concerns about nuclear radiation in Koriyama, west of the tsunami-crippled Fukushima Daiichi nuclear power plant. Toru Hanai / Reuters. March 10, 2014