Every year, millions of people across the planet turn off the lights between 8:30 pm and 9:30 pm on the last Saturday in March, this annual tradition is known as 'Earth Hour'. The goal of this activity is to spread awareness about sustainability and climate change.

This year, the lights at Tehran Azadi were turned off to mark the Earth Hour as a message to raise awareness about energy consumption and climate change last night.

Source: Mehr News agancy