Welcome to Taj mahal, those are shadows of the tourists who are stuck at the entrance with taking selfie. you can see one of the small dome is caged as a part of cleaning the marble and which is very interesting.no chemicals are used, the marble undergo a mud mask that experts say will brighten it and unclog its pores for a youthful, radiant glow. The mud will cover the iconic dome roof – and other canopies – and is apparently the best way to remove the yellow stains caused due to air pollution.