Lucknow: India's white marvel, the Taj Mahal, acquiring yellowish hues has prompted authorities in Agra to ban burning of cow dung cakes for cooking near the 17th century monument.

The Agra district administration is also planning to ban use of coal by small industrial units making bangles and famous local sweet - 'petha' to protect the Monument of Love.

"A recent study published in an American journal says that due to brown and black carbon particles, the white marble of the Taj Mahal is turning yellow. Taking note of this, we have banned use of cow dung cakes used for cooking purposes in the city," Divisional Commissioner, Agra, and Chairman Taj Trapezium Zone, Pradeep Bhatnagar told PTI.

Accepting that it would be a challenging task to implement the ban, he said a fine would be imposed as per the Nagar Nigam Act on those flouting the order aimed at protecting the UNESCO World Heritage.

Asked about the inconvenience caused to the poor due to ban on burning of cow dung cakes, Mr Bhatnagar said officials have been asked to organize special camps to distribute LPG connections to them.

He said a ban on coal-based 'petha' units in the city and bangle making units in adjoining Firozabad district was also on the cards as these emitted black carbon soot.

Besides, over 4,000 diesel-run trucks and tempos would be asked to switch over to CNG by July.

"We have asked petha and bangle-making units in Agra and Firozabad to switch over to other means as they generate black carbon that gets settle on the Taj," Mr Bhatnagar said.

He noted that burning of cow dung cakes and coal-based units generate brown and black carbon that gets settled on Taj Mahal due to which it was turning yellow.

"These carbon particles do not get washed away in rains and it was difficult to erect scaffolds around the Taj Mahal to treat the marbles chemically. There was no other option but to take this initiative," he said.

Mr Bhatnagar said Parliament's committee on environment, too, has taken cognizance of the increasing effect of pollution on the Taj Mahal and has sought reply from the district administration on actions being taken to prevent it.

About other measures, he said they were studying National Green Tribunal recommendations of retiring vehicles that were 15 years old and could implement the suggestions in the city.

The Taj Mahal acquiring a yellow hue was reported during a research conducted by experts from US universities - Georgia Institute of Technology and University of Wisconsin - as well as Indian Institute of Technology-Kanpur and Archaeological Survey of India.

"The particles causing discolouration of marble surface are dust, organic carbon (brown carbon) and elemental carbon (black carbon). Percentage-wise, 59 per cent of discolouration is due to dust, 38 per cent from brown carbon and 3 per cent from black carbon," the study showed.