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Science
Black Crust Threatens Humayun's Tomb: Air Pollution Drives Decay
✍️ Hindustan Times
🗓 02 Aug 2026, 08:38 PM
👁 1
A black crust has begun to erode Humayun’s Tomb in Delhi, scientists say air pollution is the main culprit. Experts recommend regular maintenance, protective coatings and ongoing monitoring to halt the damage.
A dark, powdery crust has started to accumulate on the marble façade of Humayun’s Tomb in Delhi, raising alarms among conservationists. The mausoleum, a UNESCO World Heritage site, has been exposed to this deterioration for several months, according to researchers from the Indian Institute of Technology and the Archaeological Survey of India.
Studies indicate that high concentrations of particulate matter and sulphur dioxide in Delhi’s air are reacting with the stone, forming iron sulphate deposits that accelerate weathering. The blackening not only mars the monument’s aesthetic value but also compromises its structural integrity.
To counter the damage, experts advise a three‑step approach: first, regular cleaning and maintenance to remove existing deposits; second, application of protective, breathable coatings that shield the stone without trapping moisture; and third, continuous monitoring of air quality and stone condition to assess the effectiveness of interventions.
If left unchecked, the decay could lead to irreversible loss of architectural details and threaten the monument’s status as a cultural icon. The government’s prompt action is essential to preserve this heritage landmark for future generations.
Studies indicate that high concentrations of particulate matter and sulphur dioxide in Delhi’s air are reacting with the stone, forming iron sulphate deposits that accelerate weathering. The blackening not only mars the monument’s aesthetic value but also compromises its structural integrity.
To counter the damage, experts advise a three‑step approach: first, regular cleaning and maintenance to remove existing deposits; second, application of protective, breathable coatings that shield the stone without trapping moisture; and third, continuous monitoring of air quality and stone condition to assess the effectiveness of interventions.
If left unchecked, the decay could lead to irreversible loss of architectural details and threaten the monument’s status as a cultural icon. The government’s prompt action is essential to preserve this heritage landmark for future generations.