Japan lifted its mandatory evacuation order over parts of the town of Okuma, which hosts the crippled Fukushima No. 1 nuclear power plant, on Wednesday as planned, citing the lower radiation levels achieved through decontamination work and progress in infrastructure development.

The order had been in place since 2011, when a deadly earthquake and tsunami in the country's northeast triggered one of the world's worst nuclear disasters, forcing Okuma's roughly 10,000 residents to flee.

However, even after the lifting of the order, around 60 percent of the town's land area where the level of radiation is the highest will remain closed.