> What's with the puddles?

What's with the puddles?

Posted at: 2015-01-07 
Birch pollen is yellow, and comes in huge quantities.

Tree pollen, good old allergy season.

Acacia pollen?

Pollen definitely.

It's obviously May, and there was a big storm yesterday. All the puddles now have yellowish borders and I've seen this before. What causes the borders of the puddles appear yellow? Is it the factory nearby, is it pollen?