Budapest is overrun with swarms of ephemerides, which appeared earlier because of the heat and low water level of the Danube.

This summer, Budapest is experiencing a spectacular invasion of ephemerids, which have appeared earlier than usual due to high temperatures and low Danube water levels. Experts say the insects, which live for just a few hours, are an indicator of the health of the aquatic ecosystem. This year, favorable conditions for algal growth have contributed to the proliferation of mayfly larvae, also affecting commercial shipping on the river.