Taj Mahal is regarded as eighth wonder the world. Millions of people from India and from abroad visit this great historic monument every year. They appreciate the architecture and the carvings. It is indeed, very prestigeous for every Indian. But over the years, it has faced immense pollution problems. It has lost its Iustre due to the presence of traces of hydrogen sulphide and other pollutants present in air.
(i)What is the main reason for the damage done to Taj Mahal and other historical monuments ?
(ii) How is damage actually caused ?
(iii) Suggest some ways to check the pollution ?

Explanation

(i) The historical mounments like Taj Mahal and others are made of marble which is basically calcium carbonate `(CaCO_(3))`. It slowly loses its Iustre mainly by acid rain.
(ii) The oxides of nitrogen `(NO,NO_(2)"etc".)`and of sulphur `(SO_(2), SO_(3))` are being constantly released in the atmosphere.They dissolve in rain water to form nitric acid `(HNO_(3))` and sulphuric acid `(H_(2)SO_(4))`. These acids react chemically with `CaCO_(3)` (marble).
`CaCO_(3)+2HNO_(3)rightarrowCa(NO_(3))_(2)+H_(2)O+CO_(2)`
`CaCO_(3)+H_(2)SO_(4)rightarrowCaSO_(4)+H_(2)O+CO_(2)`
These statues are therefore slowly corroded. Moreover traces of hydrogen sulphide present in the air are also blackening these white statues and as a result, they are gradually losing their lustre.
(iii) The Goverment of India has already taken very strict measures to safeguard this historical monument. It has been made mandatory for all Industrial units which fall in the Taj Trapezium to use LPG and CNG as fuels instead of traditional fuels. However, it is the moral duty of all to save these monuments from pollution. There should be strict instructions by the Government not to issue any licences for those units which cause pollution. The industrial houses must also observe proper norms to check pollution. Strict fines must be imposed on the defaulters.