A new study, published in the journal Lighting Research & Technology, has revealed that much of light pollution, which negatively impacts human health and animal migrations and wastes energy, is not coming from streetlights. The study indicates that much of the light and energy used at night to illuminate streets and buildings is wasted. Consequently, the wasted light ends up in the sky and disrupts wildlife. Among the sources that cause most light pollution include stadium floodlights, advertisements, facade lighting and parking lots. According to the International Dark-Sky Association, about 35% of artificial lighting at night is poorly aimed. In other words, the light does not serve the intended purpose and ends up as wasted light. This equates to about $3 billion per year in wasted energy in the U.S. alone.
— source bbc.com | 30 Oct 2020