Photo/IllutrationThe Asahi Shimbun

Lawmakers are finalizing details for proposed legislation that would move three national holidays in 2020 to reduce traffic congestion immediately before and after the Tokyo Olympics.

With about 7.8 million spectators expected for the Summer Games in one of the world's most densely populated capitals, government officials were concerned about the effects on traffic brought about by security measures for the many foreign dignitaries who will attend the opening and closing ceremonies.

The plan to shift national holidays will hopefully keep many commuters at home rather than converging on central Tokyo.

The national holidays to be moved just for 2020 will be Marine Day, Mountain Day and Health-Sports Day.

Marine Day normally falls on the third Monday in July, which would be July 20 in 2020. However, for the Olympic year, Marine Day would be moved to Thursday July 23, the day before the Opening Ceremony.

Health-Sports Day, which normally falls on the second Monday of October, or Oct. 12 in 2020, would be moved up to July 24, to make the day of the Opening Ceremony a national holiday.

Mountain Day would be pushed back one day from Aug. 11 to Aug. 10 in 2020 so it falls on the Monday after the Closing Ceremony scheduled for Aug. 9.

A multipartisan group of lawmakers plans to submit legislation in the current Diet session to allow for the moves of the national holidays. The Abe administration has looked favorably on such discussions so the bills are expected to pass.

Cabinet Office officials said there has never been an example since the national holiday law went into effect in 1948 of moving a national holiday for only one year.