___ has been causing the most damage to the Taj Mahal. (acid rain/ dust/ smoke/ pollution)
The Taj Mahal is situated in Agra. Due to a large number of power plants and industries set up around this area, the air surrounding the Taj Mahal contains oxides of sulphur, nitrogen and carbon. These oxides upon mixing with the rain water form weak acids that fall on the earth as rain. These acids upon reaction with the marble (calcium carbonate) cause its degradation. This has resulted in a gradual damage to this wonderful structure, which even today, is a major spot attracting tourists from all around the world.