Acid Rain is actually the by-product of the reaction of oxides of sulphur and nitrogen that gets mixed up with water.

The reaction is as follows:

Acid rain causes damage to buildings and structures made of stone and metal. In India, limestone is a major stone used in the construction of various monuments and statues, including the Taj Mahal.

Acid rain reacts with limestone as:

CaCO₃ + H₂SO₄→ CaSO₄ + H₂O + CO₂

This is due to which the monuments started losing its lustre and shiny appearance.