Some 530 residents of a city near the Fukushima No. 1 nuclear plant filed a lawsuit Friday demanding that the central government revoke a decision to remove their districts from a list of radiation hot spots, ending their entitlement to handouts.

The lawsuit filed with the Tokyo District Court also sought ¥100,000 in damages for each plaintiff. All are residents of Minamisoma, Fukushima Prefecture.

Lawyers for the plaintiffs said it was the first suit involving the government's decision to delist hot spots.

To be designated a hot spot, an area must exhibit an estimated radiation exposure of more than 20 millisieverts per year. While residents are not required to evacuate such areas, they are entitled to receive support in the form of subsidized medical treatment and "consolation" money.

On Dec. 28, 2014, the government removed 142 areas in Minamisoma from the list, noting that annual radiation exposure had fallen below the 20-millisievert threshold.

The plaintiffs argued that by international standards, the upper limit for radiation exposure is 1 millisievert per year, meaning the government's delisting of the hot spots conflicts with its duty to protect the safety of citizens.

The government said in a statement that its decision to delist the areas is based on scientific findings and that it has been working hard to "gain understanding from local residents."

The hot spot designation system debuted in the aftermath of the triple core meltdown at the Fukushima No. 1 nuclear plant, run by Tokyo Electric Power Co., in March 2011.