Only 100 years ago the Milky Way was visible from central Paris. Here’s how we can get the night sky back

Shielding of lights is an important aspect. Instead of having an open light, flat lights or shielded lights that prevent spill upward are crucial. They direct light to the ground, and not up into the sky.

In Canberra, the Australian Capital Territory government and light operator Omexom have been changing streetlights to do exactly this – no upward spill, and controllable lights.

In doing so, Canberra has reduced its light pollution by about 30% in only a few years, as my colleagues and I report in a forthcoming paper.