As "Le Temps" reports, there are several reasons. For one, the costs for the outdoor developments have now also been included (about CHF 60 million). As for the other 76 million, the original budget was made before the winner of the architectural competition was announced. Furthermore, the construction cost index has increased by 16 % in the last four years.
Still, the FDP is not happy with the Council of State's announcement and "calls for the architectural competition to be reopened and for a private-public partnership to be set up." There is also opposition from the ecologists, but they have been against the project from the beginning, as they wanted Genève-Servette HC to renovate their existing arena and not build a new one.
The Council of State will present the CHF 293 million investment bill by the end of the summer. If passed, it could be subject to a referendum. It thus remains to be seen whether Genève-Servette HC will be able to start construction in 2030.