Green activists and conservationists have demanded heritage city status for Agra in Uttar Pradesh, even as efforts are on to transform it into a smart city.

With three world heritage monuments, the Taj Mahal, Agra Fort and Fatehpur Sikri, two under consideration, Sikandra and Itmad-ud-daula, and dozens of other historical structures, Agra is "highly qualified" to be designated as a heritage city, say conservationists.

Sikandra is the mausoleum of Akbar. It has a perfect blending of Hindu, Christian, Islamic, Buddhist, Jain themes.

Itmad-ud-daula, the first tomb to be built in white marble, marks the departure from the red sandstone buildings of Mughal architecture, according to the official website of Agra city.

Another unique addition to Agra's rich cultural heritage is Soami Bagh, set to open on August 31 after 114 years of construction work.

Many consider Soami Bagh, the samadhi of the founder of the Radhasoami faith, as an architectural rival to the Taj Mahal because of its intricate inlay work and carvings.

The samadhi, with gothic-style pillars flanking the sides, harmoniously synthesises several architectural styles. The 193-feet-tall structure of white marble rests on a foundation of 52 wells, while the gold-plated pinnacle (kalash) weighs 5.5 tons.

Surendra Sharma, president of Braj Mandal Heritage Conservation Society, an NGO, says "Agra deserves the heritage city tag, to protect its identity. The haphazard urban growth is a huge threat to historical monuments. Encroachment around monuments and mushroom growth of colonies should be discouraged."

The Supreme Court is monitoring urban developments in Agra and the working of Taj Trapezium Zone Authority after reports suggested pollution levels in Agra and neighbourhood had increased alarmingly and could threaten the Taj Mahal.

M C Mehta, in a PIL before the Supreme Court, has raised many issues of concern, which has led the apex court to call for a "vision document" on TTZ.

This document, prepared by Delhi's School of Planning And Architecture, will be presented in the apex court this week.

Activists in Agra have drawn up an alternative vision document, which calls for heritage status for the city.

Government agencies, including Uttar Pradesh Tourism, are in favour of heritage city status, but developers and colonisers are opposing the move, fearing that the status would halt construction activities.

Agra was selected to be developed into a smart city in September 2016.