On this edition of Earth Beat: This week's show is a bit of a mixed bag - something old and something new. There's a couple of stories that avid listeners may recognise. But they're so good we just had to air them again!

Listen to the programme in full:

Windmill that looks nothing like a windmill
It’s called a Ridgeblade and it’s just had a real seal of approval - it won first prize at recent Dutch event called the Picnic Green Challenge. I caught up with the inventor, a rather stunned Dean Gregory from the Power Collective who was holding, literally and figuratively, a massive cheque for half a million euros.

Decline of a Dutch delicacy
The eel is a curious beast. Its characteristics vary so much during its lifecycle, you’d be forgiven for thinking it was several species.

The fish as infant larvae, float across the Atlantic, arriving on the west coast of Europe as tiny worms known as glass eels. These develop a taste for fresh water and swim up European rivers, where they mature for between 6 and 20 years, until an alarm bell goes off in their heads, calling them back to the ocean, thousands of kilometres away to somewhere near the Sargasso sea. Here, having spawned, they die.

And there’s the mystery. Why do they travel this far? Nobody knows. Where do the adults reproduce? Nobody knows. Aristotle had a theory that eels arose from the mud, and since no-one can prove otherwise, its still a viable, albeit unlikely, theory.

The eel population is also 1% of what it was in the 1980s. Why are their numbers declining? Again nobody knows. What we do know is that we can’t make them reproduce in captivity. Earth Beat spent a day with Dutch fishermen in the northern province of Friesland as they attempted to replenish stocks by “un-fishing” - taking fish grown in tanks and releasing them into the water.

Mumbai’s no honking campaign
Traffic and the noise it produces seem to be a necessary evil – an inevitable consequence of living in an urban environment. But does it have to be that way? Our Mumbai correspondent, Chhavi Sachdev, tells the story of living with this assault on her ears and a “no honking” campaign that aims to do something about it.

So good you can bin it
You could argue polystyrene foam is good for the environment as it insulates well, which means less reducing energy use. But overall it probably comes out on the side of environmental disaster. It doesn’t breakdown, and the production of it uses oil and releases CO2. And where does it go once it has been used? Wherever it ends up, it’s plastic and doesn’t break down.

A new kind of polystyrene foam made from sugarcane fares much better- it can be composted after use. It’s a new discovery made by an Etten Leur company and Wageningen University. Thijs Westerbeek went to check it out.

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