NEW DELHI – A new study has confirmed that severe air pollution in India’s capital, Delhi, is causing significant damage to the Red Fort, one of the city’s most iconic monuments. The research, published in the scientific journal Heritage, found that pollutants are forming “black crusts” on the monument’s red sandstone walls, threatening its intricate carvings and architectural integrity.
The study, conducted by researchers from India and Italy between 2021 and 2023, is the first of its kind to comprehensively examine the effects of air pollution on the 17th-century fort.
The Findings
Researchers found that particulate matter (PM2.5 and PM10) and other pollutants in the air have chemically reacted with the stone, creating deposits between 0.05mm and 0.5mm thick. These “black crusts” are progressively damaging the fort’s surface.
Beyond surface blackening, the study found evidence of blistering and flaking on the walls, arches, and delicate stone carvings.
The researchers noted that while the deposits can be removed in their early stages, their continued formation could lead to permanent damage if left unchecked.
A Broader Problem
The findings on the Red Fort are not an isolated case. Delhi is consistently ranked among the world’s most polluted cities, a problem that intensifies during the winter months. Conservationists have long warned about the threat this poses to heritage structures.
In 2018, India’s Supreme Court raised similar concerns about the Taj Mahal, noting that air and water pollution had caused the white marble mausoleum to turn yellow and greenish-brown.
Recommendations for Conservation
The study recommends the timely implementation of conservation strategies to protect the fort. These include:
• Regular removal of the black crusts in their early stages.
• Applying stone protectives or sealants to highly-affected areas to slow down or prevent further crust formation.
The Red Fort, built by Mughal Emperor Shah Jahan, holds immense historical and cultural significance for India. It is a UNESCO World Heritage site and the location from which the Prime Minister addresses the nation on Independence Day. Its preservation is seen as critical to protecting India’s rich heritage from modern-day environmental threats.