What Are the Light Pollution Guidelines? Their Relationship to Light-Ups and Illuminations, Local Ordinances and Dark Sky Places

How do nighttime light displays—light-ups, illuminations, projection mapping and the like—relate to measures against light pollution (hikari-gai)? The Ministry of the Environment’s Light Pollution Guidelines were revised in March 2021 and include lighting used temporarily for light-ups and events as “landscape lighting.” This article sorts out the guidelines’ scope, purpose and points of consideration, as well as ordinances in Ibara City, Okayama Prefecture, Tottori Prefecture and elsewhere. We also summarize the Dark Sky Places in Japan certified by DarkSky International (formerly the International Dark-Sky Association).

What are the Ministry of the Environment’s Light Pollution Guidelines? The latest is the March 2021 revision

The Light Pollution Guidelines were drawn up by the Ministry of the Environment in March 1998 and revised in December 2006. On March 26, 2021, the ministry announced a revised edition, citing major changes in the light environment surrounding communities, such as the widespread adoption of LED lighting. The ministry’s light pollution page lists three versions: March 1998, the December 2006 revision and the March 2021 revision. As of October 21, 2026, the March 2021 revision is the latest.

The guidelines aim to curb light pollution and create a “good light environment” outdoors. They set out guidance and measures on considering the effects of lighting on people, flora and fauna, the brightness of the night sky and so on, and present a way of thinking about what lighting should be. Light pollution is defined as a situation in which the creation of a “good light environment” is hindered by the inappropriate or inconsiderate use or operation of artificial light, or by spill light, or the adverse effects thereof.

The guidelines cover all lighting that illuminates the outdoors, listing the following seven main types.

• Road lighting, security lights and street lights

• Outdoor advertising lighting (lighting attached to or built into advertisements, and video display devices such as digital signage)

• Lighting of outdoor installations (vending machines, portable signs, etc.)

• Lighting of outdoor displays (outdoor display lots at car dealerships, housing exhibition parks, etc.)

• Outdoor sports facility lighting

• Lighting of outdoor work sites

• Landscape lighting (including searchlights, light-ups and lighting used temporarily for events and the like)

The intended audience is “everyone,” with particular mention of local government officials, developers engaged in community and regional development, and the builders, designers and managers of facilities that install outdoor lighting. Neighborhood associations and merchant associations that install security lights and the like on their own initiative, and manufacturers and importers of lighting fixtures, are also included. The main text consists of chapters on the spread of LED lighting and the current state of the light environment, the environmental effects of outdoor lighting and countermeasures, and further efforts to preserve the light environment. At the end is a checklist of items to confirm at the design, installation, and maintenance and operation stages.

How light-ups and event lighting are treated: considerations for landscape lighting

The guidelines touch on landscape lighting in the chapter describing trends in the light environment. They say that with the spread of LED lighting and advances in lighting technology, local governments and private companies are making greater use of landscape lighting. Methods are also becoming more sophisticated and diverse, they say, moving from light-ups that simply illuminate structures at night to light-ups using dynamic control and colored light.

The use of light at night is also part of national tourism policy. The summary of the fifth Basic Plan for the Promotion of a Tourism-Oriented Country, approved by the Cabinet on March 27, 2026, lists “promoting early-morning and nighttime experiences of cultural properties and the like” among its “measures against excessive congestion.” The background to the wave of nighttime light events at castles, temples and shrines is covered in our feature on illuminations and projection mapping at cultural properties.

On that basis, the guidelines say it is important, when installing landscape lighting, to keep light pollution to a minimum and reconcile it with environmental conservation and energy saving. Excessive landscape lighting, or lighting that lacks consideration for its surroundings, may cause discomfort to nearby residents, degrade the nighttime landscape, harm ecosystems and interfere with astronomical observation. They also stress the importance of considering the application of relevant rules and guidelines, surveying the surrounding environment and consulting thoroughly with local residents and other stakeholders.

The chapter on countermeasures lists the following items under “appropriate use of landscape lighting and the like.”

• Avoid unnecessary exposure of light sources, flashing, movement and coloring through filters

• Carefully consider the need to illuminate nature, such as trees and water surfaces. If illuminating, survey the ecosystem and confirm that the impact is minimal. The guidelines ask that areas with rare species and the like not be illuminated

• Aim to minimize the amount of light used, taking the surrounding environment into account

• Pay close attention to light distribution control so that spill light onto anything other than the target is minimized

• Do not use searchlights for any purpose other than illuminating a specific target. Searchlights aimed at the night sky are to be avoided because of their large effect on sky brightness. Even temporary events and the like must be carried out with full consideration for the local light environment

On lighting hours, the guidelines say that depending on local characteristics, promoting late-night switch-off within limits that do not disrupt daily life should also be considered, out of consideration for protecting the starry sky and the effects on ecosystems. In the late night, when demand for lighting falls, controlling lighting to a low correlated color temperature and minimum brightness helps curb environmental effects and glare and prevent global warming. The approach to color temperature is also touched on in our article on lighting design for light-ups.

For outdoor advertising too, the guidelines note that excessive brightness and glare, movement and flashing, and garish light colors may constitute light pollution, and point out that video display devices such as digital signage can cause pedestrians discomfort through glare and the like. Since local governments often set rules on outdoor advertising lighting and the like by ordinance, they say these must be checked and observed.

There is no section dealing specifically with projection mapping. Among related existing rules and guidelines, the guidelines list MLIT’s “Projected Advertisement Guidelines” and “Projection Mapping Implementation Manual” (both 2018), along with the Illuminating Engineering Institute of Japan’s “Guide to Landscape Lighting” (1997) and others. Procedures for projection are summarized in our article on projection mapping and outdoor advertising rules, and considerations when projecting onto cultural properties in our article on projection mapping at cultural properties and the care it requires.

Light environment zones and upward light ratio: effects sorted into people, flora and fauna, and the night sky

The guidelines sort the effects of outdoor lighting into three categories: people, flora and fauna, and the brightness of the night sky. For people, they cite reduced comfort due to glare and light intruding into homes, reduced safety due to impaired visibility and the like, and effects of blue light on circadian rhythms.

For flora and fauna, they give examples such as insects like moths that are attracted to light, sea turtles that avoid coming ashore to lay eggs on beaches lit by lighting, and migratory birds that rely on moonlight and starlight to navigate. They also mention effects on crops, such as delayed heading in rice. For the night sky, they call the brightening of the sky caused by upward light scattering in the atmosphere “skyglow,” and say that as it increases, stars become harder to see and astronomical observation is affected.

The foundation of the countermeasures is the “light environment zone,” set according to local characteristics. Set from the standpoint of the local social situation, the richness of the natural environment and the preservation of local resources such as stargazing, the guidelines divide areas into four zones and give the maximum permissible “upward light ratio,” the ratio of upward light flux to the fixture’s light output.

• E1 (areas such as natural parks and rural landscapes with a low density of outdoor lighting installations): 0.0%

• E2 (areas such as villages and suburban residential areas where the surroundings are dimly lit): 2.5%

• E3 (areas such as urban residential areas where the surroundings are moderately lit): 5.0%

• E4 (areas such as the centers of large cities and entertainment districts where the surroundings are brightly lit): 15%

In announcing the revision, the Ministry of the Environment said upward light “should be reduced as much as possible.” The guidelines note that while CIE 150:2017 gives the E1 value as 0%, they set it at 0.0% to aim for more aggressive reduction of upward light and to align with the IDA’s standard values.

Local light pollution ordinances: Ibara City (Bisei), Tottori Prefecture, Kozushima Village and Takayama Village

The guidelines introduce ordinances on curbing light pollution in three types: those covering a municipality’s entire area, those applying standards only to specific areas, and environmental conservation ordinances and the like that include light pollution provisions. Here we summarize examples confirmed in the guidelines and local governments’ official materials.

Ibara City (Bisei), Okayama Prefecture

In 1989, the town of Bisei in Okayama Prefecture enacted the “Bisei Town Light Pollution Prevention Ordinance to Protect the Beautiful Starry Sky” (Bisei Town Ordinance No. 27 of 1989). DarkSky International describes it as Japan’s first light pollution prevention ordinance. The current “Ibara City Light Pollution Prevention Ordinance to Protect the Beautiful Starry Sky” was enacted on December 17, 2004 (Ordinance No. 56) and took effect on March 1, 2005. Its supplementary provisions stipulate that dispositions and procedures under the Bisei Town ordinance are deemed to have been made under the corresponding provisions of this ordinance.

The ordinance as amended in 2020, excerpted in the Ministry of the Environment’s guidelines, sets the goal that the night sky in the Bisei area of Ibara City should not become brighter than in the previous year (Article 4). The outdoor use of floodlights (searchlights, spotlights, lasers, etc.) is prohibited in principle (Article 11, Paragraph 2), except where use is not continuous or the lights are judged to be clearly aimed at or below the horizontal.

It also prohibits lighting buildings, signs and the like by projecting light from below upward (same article, Paragraph 4), and encourages switching off outdoor lighting from 22:00 until sunrise (Article 16). The enforcement regulations specify light sources such as LED lighting with a correlated color temperature of 3,000 K or less or low-pressure sodium lamps.

Tottori Prefecture

Tottori Prefecture enacted the “Tottori Prefecture Starry Sky Conservation Ordinance” in 2017. According to the prefecture, using searchlights and other floodlights or lasers pointed at the sky outdoors at night has been prohibited in principle throughout the prefecture since April 1, 2018, because of their large impact on the starry sky, except when illuminating a specific target. Floodlights are lighting fixtures made to emit strong light in a particular direction, for example by using reflectors or lenses, regardless of the type of light source.

There are seven exceptions. In addition to protecting human life, body and property, preventing crime and ensuring traffic safety, they include use at events lasting no more than one day that have been notified to the governor in accordance with the regulations. The prefecture advises that when floodlights and the like are used at events of one day or less, such as outdoor concerts, notification must be submitted to the prefecture at least seven days before the day of use.

The ordinance allows areas with an excellent starry-sky environment to be designated “starry sky conservation areas,” with “starry sky conservation lighting standards” covering the position of fixtures, direction of illumination, luminance and so on set for each area. Designations began with Saji-cho in Tottori City (No. 1) on April 1, 2018, and now total seven areas: Saji-cho, Nichinan Town, Wakasa Town, Sekigane-cho in Kurayoshi City, Hino Town, Yazu Town and Kofu Town. The prefecture says these cover one-third of its total area. In fiscal 2026, it offers subsidies for the cost of replacing or modifying lighting to meet the standards and for regional promotion projects that make use of the starry sky (such as holding events).

Kozushima Village, Tokyo, and Takayama Village, Gunma Prefecture

According to the Ministry of the Environment’s guidelines, Kozushima Village in Tokyo enacted the “Kozushima Village Starry Sky Park Ordinance” and the “Kozushima Village Light Pollution Prevention Ordinance to Protect the Beautiful Starry Sky” when applying for Dark Sky Place status. They regulate the brightness and hours of outdoor lighting, and the island’s outdoor lighting was retrofitted to an upward light ratio of 0.0% and a correlated color temperature of 3,000 K or less. Takayama Village in Gunma Prefecture’s “Light Environment Ordinance to Protect Takayama Village’s Beautiful Starry Sky” encourages switching off outdoor lighting from 22:00 until sunrise.

Where are Japan’s Dark Sky Places? The four sites certified by DarkSky International

Dark Sky Places are certifications under the International Dark Sky Places Program launched in 2001 by the International Dark-Sky Association (IDA, now DarkSky International). According to the Ministry of the Environment’s guidelines, in addition to dark night skies, they require strict standards for outdoor lighting and education and awareness activities on light pollution. Outdoor lighting standards include an upward light ratio of 0.0% and a correlated color temperature of 3,000 K or less. Even after certification, ongoing education and awareness activities and efforts to monitor sky darkness to confirm it has not brightened are required.

The four certified sites in Japan that can be confirmed on DarkSky International’s website are as follows (as of October 21, 2026).

• Iriomote-Ishigaki National Park (Ishigaki City and Taketomi Town, Okinawa Prefecture): International Dark Sky Park, 2018. According to the guidelines, it became Japan’s first certified site in March 2018. The certification was provisional because many outdoor lights still needed retrofitting, and Ishigaki City and Taketomi Town planned to retrofit outdoor lighting in the park to light-pollution-conscious fixtures by fiscal 2023

• Kozushima (Kozushima Village, Tokyo): 2020. The site lists it as “Kozushima Dark Sky Island” in the International Dark Sky Park category. According to the guidelines, the entire village (18.58 km²) was certified as Japan’s second Dark Sky Place in December 2020, the first time an entire municipality was certified in Japan

• Bisei (Ibara City, Okayama Prefecture): International Dark Sky Community, 2021. According to Ibara City, it was certified as of November 1, 2021 (local time in Arizona, US), becoming Japan’s third Dark Sky Place and Asia’s first Dark Sky Community. Toward certification, a total of 740 lights were retrofitted: 389 security lights in the town, 344 lights at 67 city facilities and 7 road lights under prefectural jurisdiction

• Minami-Rokuroshi (Ono City, Fukui Prefecture): Urban Night Sky Place, 2023. In an August 21, 2023 announcement, DarkSky International said it was Japan’s fourth certified site and Asia’s first Urban Night Sky Place

Some local governments position dark night skies as a local resource. At a city council session in February 2020, Ibara City set out a policy of seeking certification in the community category of Dark Sky Places while pursuing a “Village of Stars Community Development Promotion Project,” aimed at raising the brand value of its starry skies and promoting itself nationwide as a “village of stars.” Tottori Prefecture subsidizes regional promotion projects that make use of the starry sky in its starry sky conservation areas.

Frequently asked questions

Are light-ups and event lighting covered by the Light Pollution Guidelines?

Yes. The guidelines list “landscape lighting (including searchlights, light-ups and lighting used temporarily for events and the like)” among the lighting they cover. For landscape lighting, they call for avoiding unnecessary exposure of light sources, flashing, movement and coloring through filters, and for light distribution control to curb spill light, among other things.

Do the guidelines have standards for projection mapping?

There is no section dealing specifically with projection mapping. Among related existing rules and guidelines, they list MLIT’s “Projected Advertisement Guidelines” and “Projection Mapping Implementation Manual” (both 2018) and others. Procedures when projections are treated as outdoor advertising are set by local ordinances.

How can searchlights be used at events in Tottori Prefecture?

According to the prefecture, using floodlights or lasers pointed at the sky outdoors at night is prohibited in principle throughout the prefecture, except when illuminating a specific target. Use at events of one day or less, such as outdoor concerts, falls under the exceptions, but notification to the prefecture is required at least seven days before the day of use.

Where are Japan’s Dark Sky Places?

The four certified sites in Japan that can be confirmed on DarkSky International’s website are Iriomote-Ishigaki National Park (2018), Kozushima (2020), Bisei in Ibara City (2021) and Minami-Rokuroshi in Ono City, Fukui Prefecture (2023).

Check specific procedures with the office responsible for each ordinance or program.

Articles organized by each stage of planning are gathered in our guide for those planning projection mapping and light events.

*Top image: The starry sky over Kozushima (from Kozushima Tourism Corporation’s press release)

*This article was compiled by the TOKYO ART SPHERE editorial team based on official announcements and public materials from each agency and organizer (as of October 21, 2026).

Text: TOKYO ART SPHERE Editorial Team

A note from the publisher

HITOHATA, INC., an affiliate of HITOHATA ASSOCIATION, the general incorporated association that operates TOKYO ART SPHERE, plans, directs, produces and operates projection mapping at National Treasures, Important Cultural Properties, World Heritage Sites and urban landmarks, as well as immersive exhibitions. It offers consultations at the stage of applying the processes, costs and procedures covered in this article to specific venues and budgets. Inquiries, including those at the stage before a budget is set, are accepted through HITOHATA, INC.’s contact form (which has an option for local government and public projects). The company’s past work is introduced on HITOHATA, INC.’s project portfolio page.