The Taj Mahal, a grand marble mausoleum completed in 1653, is under threat from a tiny mosquito-like insect.

But humans are to blame.

India's National Green Tribunal, an environmental court, has issued notices to various governmental bodies warning of the threat posed by the insect Chironomus calligraphus. Over the last several years, populations of these mosquito-like insects have exploded around the Taj Mahal because they're attracted to the white sheen of the marble. The swarms are leaving behind greenish-black feces, which is discoloring the ancient monument.

Chironomus plumosus Chironomus plumosus, pictured above, is similar to the flying insect that is currently threatening the white marble of the Taj Mahal. (Photo: Wikimedia)

The sudden increase of Chironomus calligraphus is due to the stagnation and pollution of the Yamuna, a major river that flows near the monument in Agra. The unregulated dumping of solid and liquid municipal waste into the river has led to a surge in algal growth and phosphorus, the primary food for these insects.

While the green discoloration can be washed away by water, environmental activists see the insects' impact as more a warning of the environmental degradation occurring all around the Taj.

"The deposit on the Taj is water soluble," archaeologist Bhuvan Vikram Singh told the Times of India. "We are trying to clean it with water. But cleaning the Taj Mahal with water will not solve the problem. We know where and how these insects grow, so if we solve the problem at the basic level, we can stop them from growing in numbers and there will be no marks on the Taj."

But it's not just insects that are changing the color of the Taj Mahal. The city of Agra where the monument is based has some of the highest levels of atmospheric black carbon in the country. A two-year study by the Dayalbagh Technical Institute also found high levels of "suspended particulate matter and particulate matter" compared to permissible levels. This rampant air pollution, together with dust, has given the Taj Mahal an unsightly yellow tinge. (You can learn more about the damage being caused by air pollution in the video below.)

D.K. Joshi, the same activist who raised the alarm over the insect invasion, slammed government officials in 2013 for failing to do anything to address the worsening environmental conditions in Agra.

"We neither have water, nor power; the sewage system does not work, community ponds have disappeared; trees have been chopped up; and the Yamuna river continues to wail and scream," he decried. "Nothing has changed, conditions have worsened."