The July 31 election of a new Tokyo governor threatens a much-loved fixture in the city's calendar: the annual Sumida River Fireworks Festival.

Yoichi Masuzoe left office Tuesday in an expenses scandal, and city residents will now have to pick a successor.

The fireworks are planned for either July 30 or 31. Organizers typically reserve a full weekend in case inclement weather on Saturday forces them to postpone the display to Sunday.

Setting July 31 as election day deprives them of that buffer, as staffing constraints mean the two events cannot coincide, meaning fireworks officials will be praying that July 30 has no wind or rain.

"Cancelation would indeed result in an economic loss," Wataru Nakagawa of the festival's organizing committee told The Japan Times.

The massive display of about 20,000 fireworks, some of them the world's most elaborate, takes place simultaneously at two launch locations on the Sumida River.

The spectacular display can be viewed from areas such as Sensoji Temple in Asakusa, Tokyo Skytree or the Ryogoku Kokugikan sumo arena. This year's display, the 39th, will cost around ¥170 million.

The display has its roots in the historic Ryogoku Kawabiraki Fireworks festival, which began in 1733 as a Shinto rite. It was revived in 1978 as an annual attraction and has most recently been drawing around 960,000 spectators.

Nakagawa said that when the new gubernatorial election date was announced, the committee received many queries from people worrying that the festival would be canceled.

However, Nakagawa remains upbeat about it as the committee has dealt with similar one-day windows in the past.

"In the past we considered postponing it until the next day even if that meant it coincided with an election, but we always managed to hold it according to the original plan," Nakagawa said. "It's not the first time we've set only one date."

He said the two events cannot take place on the same day because both require assistance from government officials. Police, for example, are unable to staff polling stations and the streets around the fireworks venue at the same time.

"As there are several poll locations near the venue ... it might have a negative effect on the election as, due to traffic restrictions, some people could not get there on time or would be unable to vote," Nakagawa added.

The organizers are now correcting information on hundreds of posters put up around Tokyo to promote the event.

The festival is organized with the assistance of the Tokyo Metropolitan Government, which gives a grant of some ¥36.6 million and helps to promote the event.