Authorities in India's northern Uttar Pradesh state deployed air purifiers to protect the historic Taj Mahal monument on Monday.

In Agra, home to the Taj Mahal and one of the world's most polluted cities, officials have rolled out two air purifier vans that can purify 15 lakh cubic meters of air in eight hours.
"We just came back after visiting the Taj Mahal but there was fog, we couldn't see anything," said a tourist from Mumbai, Rituraj Somnath Patil.
Pollution is turning the Taj Mahal yellow, despite efforts by the Indian government to control air contamination around the poignant 17th century monument and keep it shimmering white.
One of the seven Wonders of the World, the Taj Mahal flanks a garbage-strewn river and is often enveloped by dust and smog from belching smokestacks and vehicles in Agra.