Acid rain, caused by atmospheric pollutants like sulfur dioxide and nitrogen oxides, is a major cause of damage to historical monuments. The Mathura refinery is located relatively close to Agra, and its emissions are a significant source of sulfur dioxide in the region. Growing population (B) and pollution from tanneries (D) contribute to general pollution but are not the primary cause of stone cancer. Climate change (C) can exacerbate damage but is not the primary direct cause.