This Europe: Switch off nation's lights and help save the insects - and the people - says astronomer

Jan Hollan is fighting for a darker future for the Czech Republic. The astronomer is leading the campaign to implement a law that made this formerly communist country the world's first nation to ban light pollution, an intrusion of the modern age which Mr Hollan and others say disturbs wildlife, poses a menace to people and spoils stargazing.

Anti-light pollution measures are on the books in several US states, parts of Australia and in the Italian region of Lombardy. But the Czech legislation, adopted in 2001, is the first nationwide law banning light pollution, says David Crawford, executive director of the International Dark-Sky Association, a non-profit organisation from Tucson, Arizona. "We must preserve the night environment for so many reasons, and this law helps us do that," he says.

The night sky above Brno, a city of 400,000 people 125 miles south-east of Prague, has become so bright that only experts using telescopes can see traces of the Milky Way, says Mr Hollan, 47, who works at the Nicholas Copernicus Observatory and Planetarium here. Mr Hollan hopes the Milky Way will reappear in a decade if Czech lawmakers fine-tune the law with rules requiring that new or replacement lamps be of designs that do not emit light upward or sideways.

The 2001 law only ordered that light pollution be reduced, without setting any specifics on how it should be done.

New rules pending before parliament would require street lamps and other lighting systems to be dimmed overnight and lamps illuminating signs and buildings to be weak and targeted. The rules would also ban "sky-beamers" (lamps that emit pillars of light into the sky) and ensure that lamps near protected nature areas would be shielded.

The changes would be good for humans and wildlife, Mr Hollan says. Sky-beamers often attract birds that end up flying in endless circles around the ray, he said. And regular street lamps attract insects from up to half a mile away, while stronger lights attract insects from up to four times as far. That means lights near nature reserves "suck - like vacuum cleaners - all the insects out", Mr Hollan says.

For humans, light pollution means sleeping problems, and glaring lamps can cause traffic accidents because they blind drivers, he adds. Two 2001 studies found that women working overnight shifts, and exposed to less darkness, had higher rates of breast cancer.

Darkness is required for the body to produce the hormone melatonin, and researchers say that when melatonin secretion drops, oestrogen levels tend to rise. Increased oestrogen levels have been linked to breast cancer.