This monument is damaged due to acid rain. This phenomenon is famously known as _________.
Taj Mahal is damaged due to acid rain. This phenomenon is called ___ .
Taj Mahal is one of the strongest monument and is made up of white marble. It is damaged due to acid rain. This phenomenon is called:
During rains, river water becomes muddy but after a few days it becomes clear. This phenomenon is due to _______.