The Diet on Wednesday enacted a law to move national holidays to days linked to 2020 Olympic ceremonies, to alleviate traffic congestion in the Tokyo metropolitan area.

The revised law is aimed at ensuring smooth transport and security for the Tokyo Games.

The days of July 23, the eve of the games; July 24, the day of the opening ceremony; and Aug. 10, the day after the closing ceremony will be made holidays, as many important guests, including foreign dignitaries, are expected to travel to and from Japan on these days.

Marine Day, on the third Monday of July, will be moved to July 23; Sports Day, on the second Monday of October, will be moved up to July 24; and Mountain Day, on Aug. 11, will shift to Aug. 10.

Tokyo Gov. Yuriko Koike, who is overseeing preparations for the event, said she appreciates the central government's cooperation and that the decision to move holidays will help resolve transportation problems.

"The success of the Olympic Games will depend on enabling smooth transportation and commitment to ease traffic before and during the opening and closing ceremonies, but also throughout the whole tournament," the governor said in a statement Wednesday. "The Tokyo Metropolitan Government is also encouraging residents to commute to work using early-morning trains to ease overcrowding, work from home or go on holidays during the Olympics."

On the same day, the Diet also enacted the nation's first law to prevent doping. The law allows the sports minister to ask customs and immigration authorities, as well as police, to provide personal information on athletes as part of efforts to detect illicit practices by Olympic and Paralympic athletes coming to the country.