Mathura refinery releases toxic gases (like oxides of sulphur) which causes acid rain and hence corrosion of the marbles of Taj Mahal.

The Mathura Refinery, is located in Mathura, Uttar Pradesh. The refinery processes low sulphur crude from Bombay High, imported low sulphur crude from Nigeria, and high sulphur crude from the Middle East. The Mathura oil refinery releases toxic gases and disposes waste into the rivers making the area dirty and unhealthy. the air has high levels of suspended particulate matter, caused by factory emissions, dust, construction, and exhaust from automobiles. These are causing the Taj Mahal to change color