Kiyoshi Kimura, president of sushi restaurant chain Sushi-Zanmai, displays a 200 kg bluefin tuna at his main restaurant near Tsukiji fish market. The bluefin tuna was traded at $117,000 at the wholesale market on the first trading day of the new year. [Photo/Agencies]

On a recent year-end day, shop owners in rubber boots and aprons were rushing to clean up and sell off the last of their inventory, as the last few hundred shoppers milled around hunting for bargains.

Already, some shops outside the market have been razed and a new building that will house a smaller "outer market" is under construction. Conceptual drawings from the Tokyo city government show the 23-hectare market site that fronts the Sumida River's outlet into Tokyo Bay being transformed into an open waterfront park surrounded by greenery, with a wide shopping plaza and a passenger terminal for tourist ferries traversing the bay and river.

"We are contributing with all our efforts to the revitalization of our historic Tsukiji," says a banner emblazoned with the logos of the architect and other contractors hanging from scaffolding of the new building.

Tsukiji's predawn auctions are a fixture on the tourist circuit, and since it was not set up to accommodate large crowds the management has gradually limited access for safety's sake.

Planning for the move began nearly 20 years ago. But the shift was delayed for years due to toxins found in the soil at the new location, the former site of a coal gasification plant run by Tokyo Gas.

The city announced in 2001 that the market would be moved by 2012. But cleanup work dragged on, and in 2013, Tokyo Gas disclosed it had found more toxins at the site.

Critics of the move said city authorities were swapping worries over cramped and some say unhygienic conditions in Tsukiji for a new set of health problems: Unsafe levels of lead, arsenic, hexavalent chromium and other toxins.

Cleanup of the tainted site required the removal and replacement of 2 meters of topsoil, construction of retaining walls, pumping out of polluted ground water and an injection of fresh water.