discolouration of the taj mahal, india

acid agra archaeological architecture biomass black brown burning carbon changing childbirth deposits died discolour discolouration emission emitted environmental fossil fourteenth fuels garbage georgia greatest greyish grieve heritage historical history hues india indian indo institute ivory journals landmark love mahal makrana marble mausoleum minaret monument mughal mumtaz muslim particles persian pollutants poor princess rain science shahjahan site story survey suspended tajmahal technology trapezium unesco university white wisconsin wonders world yellowing yellowish zone