However, conservationists say that the crisis the Taj confronts comes not merely from nature and pollution but also from people themselves - too many tourists and too many vehicles that bring them to Agra.
Eco-activist Shishir Bhagat, president of Wake UP Agra, says: "The number of vehicles in the city has shot up from just around 40,000 in 1985, when Firozabad was part of Agra district, to almost 800,000 now. The air is loaded with pollutants."
Originally described as "Bagh e Baahist", a heavenly garden, the Taj Mahal has now degenerated into just another popular tourist spot, according a historian.
"When thousands of tourists 'invade' the serene monument every day, leaving behind hand and foot marks on the white stones, and tonnes of noxious gases through breathing, the cumulative affect on the fragile structure is huge," historian R.C. Sharma told IANS.
According to him, while many tourists are genuinely aware of the historic significance of the monument and its great heritage value, there are others who care nothing for the sanctity of the Taj.
The human-load is increasing every year and is taking its toll. Last year more than four million people visited the Taj. The entry is free for children below 15 years.
"Each Friday, when the mausoleum is closed for tourists, Muslim faithfuls are allowed free entry to offer prayers. During the annual Urs of emperor Shah Jahan, the entry is free for three days and the number exceeds 50,000 daily," Rajeev Tiwari, president of the Tourism and Travel Agents Association, told IANS.
Tiwari recalled that in the past a visit to the Taj was "almost like a spiritual journey to a shrine".
According to heritage photographer Lalit, "the hyped-up romanticism attached to the monument and the guides spinning out cheap gossipy yarns to titillate the tourists have in a way defiled the sanctity of the structure".
Abhinav Jain, a tourism industry leader, said: "The mausoleum must have been originally designed for 50 or 100 visitors a day. But now there is no end. With the tourism department and the Agra Development Authority making extra efforts to promote tourism, the number will continue to rise."
According to Jain, there has to be a better way of regulating visitors inside the Taj.
He said: "It is time they had a system in place, allowing a specific number of visitors inside the Taj for a fixed period. Also online reservation facility should be made available so that the entry is orderly and spread out."
To a casual observer the iconic white marble monument looks pale, jaundiced, fatigued and sick. The vibrant freshness of the past is missing, said Sandeep, a hotelier of Taj Ganj.
According to Ved Goutam, a tour guide, Agra has already become a desert.
"When you see the camels moving around on the dry river bed, one gets the impression that Agra is in a desert, a part of the Rajasthan state," he said.
The Archaeological Survey of India (ASI) has restored the Mehtab Bagh at the rear of the Taj Mahal and the state forest department has developed a dense green buffer along the river bank on the opposite side.
But the major problem is the Yamuna, which has been reduced to a "sewage canal."
Shyam Singh Yadav, retired chief horticulturist of the ASI, said "it was a herculean task developing a well laid out green heritage garden behind the Taj".
However, conservationists remain worried whether this small patch of green can insulate the Taj from the high SPM (suspended particulate matter) level at the peak of the summer.
"If there is no fresh supply of water in the river that touches the Taj foundation to provide a shock-absorbing buffer to insulate the building from seismic movements, the fear is that the monument could tilt, cave in or struggle for stability," said Surendra Sharma, president of the Braj Mandal Heritage Conservation Society.
