Union Environment Minister Harsh Vardhan said a study had found that the white marble of the historic monument was turning yellow due to carbon pollution.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/petrol-diesel-vehicles-banned-within-500-metre-taj-mahal-harsh-vardhan
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/ndtv
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/uttar-pradesh
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/agra-t
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/vehicular-pollution
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/taj-mahal
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/ministry-environment-and-forests-moef
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution-control