Question

Why is Taj Mahal turning yellowish?state the process and define it.

Answer 1

Due to global warming

Answer 2

Taj Mahal is turning yellowish , one of the major reason is  air pollution, and Taj Mahal is made up of white marble.Marble which doesn't exist in pure form , it's includes with minerals so those minerals oxidises and discoloration occurs.Taj Mahal is around 300 years old so little discoloration is obvious.