Shamshuddin Khan has been showing visitors around the Taj Mahal for more than 30 years. During that time he has been a tour guide to more than 50 world leaders - recent guests have included the Sri Lankan president and the Israeli prime minister.

Over the past three decades, he says, his hair has turned greyer, but the Taj Mahal has become darker. Approaching the building, Khan points out the cracks and the decaying marble of the structure.

“There are embarrassing moments when the foreign tourists ask me why the Taj Mahal is not being maintained the way it should have been. They also ask us why it is losing its colour and shine. We guides have no answers.”