Since the time the Ugrasen Ki Baoli - an example of traditional rainwater harvesting - was built, it has had ample water till about a decade ago.
The water table at the 14th century structure - under protection of the Archaeological Survey of India (ASI) - has, however, drastically gone down since 2005, according to the Central Ground Water Board (CGWB).
Environmentalists have blamed Delhi Metro's underground line connecting Rajiv Chowk and Pragati Maidan for turning the water body dry. The Barakhamba-Dwarka stretch became operational on December 31, 2005 and the Barakhamba-Indraprastha portion on November 11, 2006.
"De-watering during the construction of Rajiv Chowk station and the tunnel between it and Mandi House station led to plummeting of the water table," said Manu Bhatnagar, head of NGO INTACH's Natural Heritage Division.
Environmentalist Manoj Misra said, "Tunneling disrupts aquifers. When the DMRC planned the Barakhamba-Mandi House stretch, this aspect should have been studied in environment impact assessment (EIA)."
Stating that EIA is done only to assess effect on the surrounding flora and fauna, a DMRC spokesperson said, "There are no reports to suggest that metro has caused any harm to Delhi's water table."
"While a site is de-watered during construction, water is diverted to nearby areas. After construction is over, the tunnels are closed and so our construction does not impact the water table in the long run," added Jitender Tyagi, DMRC's director (works).
On the other hand, all that the ASI does is architectural maintenance. "De-silting and conservation is done regularly. But the water body can be revived only when there is sufficient surrounding area for ground water re-charge," said DN Dimri, ASI's Delhi circle chief.