The saying goes that the Taj Mahal is pinkish in the morning, milky white in the evening, and golden when the moon shines. Though this may once have been true for the famously pristine marble monument, a mixture of pollution and poor management has now burdened the Taj with a 24-hour layer of yellowy-brown.

Authorities in India are trying to work out how to scale the Taj Mahal’s majestic but delicate dome as they complete the first thorough cleaning of the World Heritage Site since it was built 369 years ago.