Do we still need the pristine night sky? Indeed, there is a problem. Globally, more than 80% of all people live under light polluted skies. The trend increases exponentially due to urbanization, road traffic, energy-efficient lighting technologies, municipal policies, and unawareness or rejection of the negative impacts of light pollution on all life forms and/or of possible solutions. Light pollution is unnecessary and / or excessive artificial light at night appearing as sky glow, glare, trespass or clutter. It fragments landscapes, harms human well-being and biodiversity, wastes energy and threatens food security. It also decreases our levels of empathy. From Geneva, Switzerland, one must travel more than 1,300 km to get away from it. In the cross-border setting of a Franco-Swiss biological corridor of Greater Geneva, we aim to tackle light pollution for sustainability. The analysis of two representative communes in the corridor shows high levels of light pollution (and an increasing rebound effect due to adoption of low energy-consumption lighting) as a result of inadequate socio-environmental policies. To reach the 2020 Aichi Biodiversity targets, mitigating the biodiversity damage potential requires a 60 % reduction of this potential loss in the perimeter, making the reduction of light pollution critical. I prioritize actions and offer ideas for policy implementation with citizen participation under a long-term sustainability approach.