An Indian archaeologist is praying for a respite from a heat wave engulfing the Taj Mahal town of Agra, warning that heavy dust in the dry air could permanently scar the marble monument to love.

Temperatures hovered this week at 45 C in the city, 200 kilometres south of New Delhi, as a heat wave that has killed 60 people nationwide in the past week dragged on.

The Yamuna River, which runs behind the 17th-century white Mughal tomb, was dry and Agra's chief archaeologist Doraiswamy Dayalan said he was worried that dust from the nearby desert and factories would turn the marble yellow.

"The dry river allows dust and suspended particulate matter to rise and flow in the air and slam into the monument's surface," said Dayalan, of the Archaeological Survey of India which cares for the Taj.

"If water returns to the Yamuna then there will be less suspended matter in the air," Dayalan said, adding that he was praying the annual monsoon rains arrived by the end of June.

Ajay Taneja, a chemistry professor at Agra University who monitors the tomb built by Mughal emperor Shah Jahan in memory of his second wife Mumtaz Mahal, agreed, saying: "This is not good for the health of Taj."

Dayalan, however, said the Taj had been built to deal with the heat that bakes India every summer.

Source: China Daily