Marble discoloration at the Taj Mahal, Agra, India, appears to be most prevalent in areas that are both shaded from early morning sun and protected from rainfall. An explanation, based on atmospheric modeling concepts, is presented that attributes, at least in part, the discoloration to the simultaneous occurrence of high concentrations of pollutants and moisture condensation on the marble surfaces in the early morning. Pollution from nearby sources is released in the vicinity of the Taj. Soon after sunrise, surface warming is known to cause a rapid increase in turbulent mixing, which draws the pollutants to the surface of the building. Since wet surfaces enhance the deposition of gaseous pollutants such as sulfur dioxide, it is hypothesized that the areas of marble still wetted by surface condensation will preferentially take up an early morning pulse of pollutants.