Delhi govt to set up STP to provide clean water for 13th century Mehrauli reservoir

For over a decade, residents have complained about the reservoir being significantly degraded by sewage seepage, sludge accumulation, and constant dumping of garbage along its banks.

After years of neglect and being turned into a dumping area, thirteenth-century water reservoir Hauz-i-Shamsi in south Delhi’s Mehrauli may soon get a solution to its pollution woes.

Officials said that about ₹35 crore has been sanctioned for the STP, which will be built over 750sqm of land.

The Delhi government has started the process for setting up a 4.5MLD (million litres a day) sewage treatment plant (STP) in southwest Delhi’s Vasant Kunj Sector A to provide clean water to the reservoir.

Officials said that about ₹35 crore has been sanctioned for the STP, which will be built over 750sqm of land. “Of the total cost, ₹15.66 crore shall be provided by the Central government’s National Mission for Clean Ganga (NMCG), while the operational and maintenance cost of ₹20.17 crore shall be borne by the Delhi government,” a senior Delhi Jal Board (DJB) official said.

Officials said the bidding process has been initiated and the construction is likely to begin soon. “The plant will be set up on a design, build and operate model, and the developer will be responsible for operating the facility for 15 years. The bidding process will be completed in February, and the construction will take about a year. Another three months would be needed for commissioning the plant,” the official said, adding that the developer will be able to select the treatment technology for STP.

For over a decade, nearby residents have complained about the reservoir being significantly degraded by sewage seepage, sludge accumulation, and constant dumping of garbage along its banks. The red sandstone found in the original structure also seems to have been damaged.

According to officials, the STP will address the complaints of polluted water being supplied to local residents, and regular supply of freshly treated water will help prevent stagnation.

The ASI-protected reservoir was built by Delhi Sultanate ruler Shamsuddin Iltutmish in the 13th century, officials said. Popularly also known as Shamsi Talab, the reservoir once spanned over 100 hectares, according to INTACH’s listing of built heritage in Delhi. However, it has now been reduced to about 7.05 acres, according to ASI.

ASI had earlier attempted to clean the reservoir back in 2015, but with little success. In 2024 and 2025, the Sustainable Environment and Ecological Development Society (SEEDS) again conducted cleanliness drives at the site under the supervision of ASI.

Flanked on one side by a dome shaped pavilion, supported by 12 stone pillars and the Jahaz Mahal on the other side, the reservoir came to be commissioned by Iltutmish, according to the List of Muhammadan and Hindu Monuments, Mahrauli Zail, Volume III, written by Maulvi Zafar Hasan in 1922, the then superintending archaeologist of ASI. Iltutmish’s dream of a prophet on a horse led him to the place where the reservoir now stands. Following the incident, Iltutmish found the hoof mark of the horse at the same location as his dream, which also happened to be a natural source of water. The pavilion was built over the hoof print of the Prophet’s horse at the same time. The Jahaz Mahal on the north-east corner of the reservoir was built in the Lodhi era.