New Delhi, Oct 22 (PTI) Calling Taj Mahal as "not a monument to experiment with", top heritage experts have raised objections to the illumination of the famed Mughal-era mausoleum, saying the step jeopardizes its marble surface due to defecation on it by insects attracted by the lighting.

According to senior officials of the Archaeological Survey of India (ASI), few low-level security lighting posts were installed a few months ago at the 17th century World Heritage Site, with a twin purpose of illuminating the Taj and wooing tourists at night.

"However, the direct illumination of the marble monument has brought with it, a big problem - insects. And, these are grass-sapping insects which sit on the floors and walls of the illuminated part and discharge their excreta on the surface, leaving a colored pigment on it, thus spoiling the flawless beauty of the architectural icon," Superintending Archaeologist (Science Branch) M K Bhatnagar said.

Located about 20 m from the base of the monument, the lightings on the Yamuna side are attracting maximum insects on that side. While the monument falls under the Agra Circle of the ASI, its security has been entrusted to Central Industry Security Force (CISF).

"We (Science Branch) have already sent a letter to the Director General, ASI, Director, Science Branch (ASI), Superintending Archaeologist, ASI Agra Circle and to the CISF requesting them to switch off the lights immediately," Bhatnagar told PTI over phone from Agra.

B R Mani, who recently retired as the Additional Director General of the ASI, expressed surprise over the move to install lighting at the world famous heritage site.

"First of all, Taj Mahal does not need lighting at all. It is a marble structure and can be seen in all its glory in natural night. It is absolutely unwise to illuminate it with artificial lighting, which attracts insects. On full moon day, one can see Taj in all its splendor. And, if the government thinks by putting up lights they can attract more tourists, then I am sorry to say this, but Taj Mahal is not a monument to experiment with," Mani said.

"And, having the monument lit up and so many people coming to see it at night, also is a potential security threat. Tourists can come once in a while to admire its beauty at night, but not on a regular basis," he added.

Sources at ASI said that there was "pressure" from the tourism ministry to install the lights, even though previous studies on the subject have suggested against it.

"There were departmental studies done around mid-2000s and these explored the impact of illumination, saying the insects attracted by the light, drop excreta on the surface, which leads to pigment deposition on the marble. Unless there is no conclusive study on this subject, Taj Mahal should definitely not be illuminated," Superintending Archaeologist, Agra Circle (ASI), Bhuvan Vikram said. (MORE) PTI KND ZMN PVI