A judge in India’s environmental court this week upbraided state officials for “making millions” from tourists visiting its iconic Taj Mahal while dumping solid waste into an adjacent river that has become a breeding ground for insects that are turning the soaring marble structure green.

“You cannot protect the Taj Mahal from which you are making millions. You are dumping municipal solid waste in Yamuna [Jumna River] just behind the Taj Mahal. Can there be a greater insult to a monument which is a wonder of the world. It is shocking,” a National Green Tribunal judge said at a hearing Friday, according to a report in the Hindu.

The panel was hearing a plea by an environmentalist D.K. Joshi alleging that dumping of municipal waste in the river, which abuts the Taj Mahal, has fostered a mosquito-like insect whose slimy excretions are causing green patches on the structure. The Archaeological Survey of India said recently that swarms of these bugs, from the genus Goeldichironomus, are attracted to the bright walls of the monument.

For decades, conservationists have struggled to preserve the incandescent beauty of the Taj Mahal — the mausoleum built by Emperor Shah Jahan in honor of his beloved wife.

Efforts have intensified in recent years when the structure began acquiring a yellowish tinge because of rampant air pollution in the industrial city of Agra and smoke from a nearby crematorium. Some nearby coal-burning factories have been shuttered and conventional cars are banned from its grounds.

So far, officials seem to be at a loss at the best way to clean the green patches, although they are in the middle of applying a mudpack therapy treatment designed to remove any impurities in the white marble.

The state’s chief minister, Akhilesh Yadav, has ordered a probe into what’s causing the green discoloration. He has vowed to preserve the “natural beauty” of the monument.

The Taj Mahal was the top attraction for the 11 million foreign visitors who came to India between May 2014 and October 2015, the government said in December.