Delhi’s deteriorated air quality is only fatal for people but it is also affecting historical buildings. What has come out in a study is also shocking and worrying. The study claimed that the impact of Delhi’s poor air quality is also being affected by the prestigious Red Fort. At the same time, people from all over the country come to see the Red Fort and the Prime Minister hoists the flag here on Independence Day.
Black layers continuously freezing on the walls- study
According to a new Indian-Italian study, the black layers of pollutants are constantly freezing on the red sandstone walls of this 17th century monument, which threatens its structure and beauty. The title of the study is-“Describing the symptoms of red sandstone and black layer to analyze the effects of air pollution on a cultural heritage building: Red Fort, Delhi, India.”
This study is the first comprehensive scientific investigation of how urban air pollution is affecting this historic monument built by Emperor Shah Jahan between 1639 and 1648. This research was done by scientists of the Indian Institute of Technology-Roorkee, Indian Institute-Kanpur, Venice ‘Foskari University and Archaeological Survey (ASI) this year under cooperation between the Department of Science and Technology of India and the Ministry of External Affairs of Italy.
Analysis of samples of black layer
The team analyzed the sandstone and black layer samples collected from different areas of the Red Fort complex including Zafar Mahal. The conclusions showed that the thickness of black layers vary from thin deposition of about 0.05 mm in residential areas to 0.5 millimeters of thick layers on the walls of high-ending areas. These thick layers are firmly connected to the surface of the stone, causing the risk of the surface uprooting and the destruction of complex carvings.
Cement factories and construction activities responsible
According to the researchers, black layers mainly contain small amounts of gypsum, basanite, vedelight and heavy metals like lead, zinc, chromium and copper. These pollutants are not found naturally in sandstone, but are accumulated from external sources, for which emissions from vehicles, cement factories and city construction activities are responsible.
The damage causes during the rain
The study highlights how chemical reactions between pollutants such as sulfur dioxide and nitrogen oxide create layers of gypsum, which eventually harm during rainfall.
Thick particle three times higher than limit
After obtaining data related to air quality from the Central Pollution Control Board from 2021 to 2023, the researchers confirmed that the concentrations of micro particles were two and a half times higher than the national border, while the coarse particles were three times higher than the limit. The level of nitrogen dioxide also crossed the safe range, causing the stone to slowly rot, while ammonia and sulfur dioxide levels were within the range.
The construction of the Red Fort started in 1639 and was completed in 1648. In 2007 it was included in the UNESCO World Heritage List. Researchers said that the Red Fort is named due to the red sandstone of the Vindhya region used in its vast walls and palaces.
2.4 km long fortifications
The fort complex is spread over a square kilometer and is surrounded by the walls of 2.4 km long fortifications, which have a height between 20 to 23 meters and their thickness is up to 14 meters. Initially, this monument, protected by the nine meter wide gap and Yamuna River, is located on the banks of the heavy traffic ‘Inner Ring Road’ today, which is exposed to excessive pollution.