Answer:
Liu notice that the old marble statue looks different from the new one also the old marble statue is rough while the new marble statue is smooth and shiny. Chemically marble is mixture of majorly Calcium oxide, Silica ,Alumina and other salts.
Since the environment is highly polluted so it enables chemical reactions on the surface of the statues and that is what causing the degradation of the statues to loose their shine and smoothness
Hence, the new statues looked smooth and shiny while the old statues looked rough and dull.