There are trees all over Saratov that have white fuzzy stuff that blows off and floats all over the place.  It looks like cotton.  Here's an explanation and a couple of pictures.

Pukh is the result of a Soviet-era experiment gone totally wrong. In efforts to make Moscow greener and create more oxygen for a healthier life, linseed trees were planted throughout Russia’s capital. The result is that these trees begin producing and releasing into the air a fluffy substance similar to cotton but much lighter, referred to as pukh in Russian. The air becomes thick with this fluffy white stuff and it looks like there’s a blizzard outside in the middle of summer.