The tradition of use of glazed tiles as a decorative element of building architecture by the Mughals can be traced to the crafts of Iran, which governed the tastes of the eastern Islamic world.

There is a profusion of tilework on other monuments in the project area like the Isa Khan’s tomb and mosque, Nila Gumbad and Atgah Khan’s tomb and of course, the Humayun’s Tomb amongst others.

In the 21st century, however, the tiles represented a craft skill lost in India. The conservation process required four years of experimentation, which was started under the guidance of master craftsmen from Uzbekistan – who trained project’s craftsmen in the craft of tile making.

Following the formation of the ASI in AD 1861 and the disruption of traditional conservation systems and the availability of cement in the 20th century most buildings were repaired with cement and though these repairs were carried out in good intention they accelerated the decay process.

Use of lime mortar in conservation works is essential as it is the original building material and if well prepared, lime mortar survives for centuries as it returns to its natural state of limestone. Original ceiling surfaces were first cleaned using water; Traced and thoroughly documented. Completely missing and partially missing pattern were completed as per original design.

For over 3000 years, stone buildings have been built in India and, consequently, repaired, conserved or renewed. Until the 19th century, enlightened master craftsmen were responsible for building as well as for regular repairs to the monumental palaces, forts, step-wells, tombs, temples, mosques that dot the country’s landscape.

Over a hundred stone craftsmen have worked for over three years on the conservation projects on Nizamuddin monuments. They have used the same tools and techniques that would have been used by craftsmen who built these structures during the Mughal times. The craftsmen have also been an integral part of decision making in the conservation process, solving complex situations due to their ingrained knowledge about stone and materials.

The monuments in the Nizamuddin Area are built majorly of sandstone and Delhi Quartzite stones. The long stretches of the garden enclosure walls which surround the tomb-gardens have been built in DQ stone, one of the hardest construction materials. This stone not only require a different set of tool, owing to its hardness quotient, but also require a particular skill in its handling and installation. There were many places where the enclosure walls were missing or collapsed at the Humayun’s Tomb, Batashewala Complex and the Bu Halima Garden. The foundations of missing portions were excavated in order to guide the reconstruction of these sections. Using the same building techniques, tools and materials employed by the original builders, the masons worked on the reconstruction of these wall portions.

The scale of Humayun’s Tomb’s finial at 18 feet was a daunting task to gild, especially since the traditional crafts of gold-foil gilding has become rare. After an exhaustive research, master craftsmen skilled in the traditional process of gilding gold onto copper were identified for the Humayun’s Tomb finial project and several rounds of experimental gilding carried out and subsequently tested for various factors, including durability, to plan for the actual gilding. Regular testing of the gold layers during the application process was carried out to ensure a consistent and high quality of the gilding.

Continuity of craft traditions over centuries in India has meant that craftsmen still use tools, techniques used by their forefathers in the 16th century to create copper vessels, kalash or finials for Temples and other similar products. However making the largest vessels of the Humayun’s Tomb finial posed significant challenges on account of the size and dimensions. Six months of continuous effort using traditional tools to beat and mould the copper sheets resulted in the assembly of all eleven vessels that comprise the finial.

Conservation of wood was one of the key elements at Humayun’s Tomb Complex. The doors of the 68 lower cells at Humayun’s Tomb were replaced with unsightly metal doors which were compromising the historic character of the tomb. A team of carpenters working closely with conservation architects and engineers worked on the procurement of the same wood, construction of doors taking references from the same period doors, and installed the new doors after appropriate seasoning of the wood. The damaged lofty doorway of Arab Serai Gate and the 20 feet log of wood inside Humayun’s tomb finial which had collapsed was also crafted by hand and installed.

A team comprising of 10-15 Bhandanis or skilled labour undertook the gargantuan task of installing the Humayun’s tomb finial atop the 70 feet high dome and transporting each vessel in a safe and secure manner. Conservation works require not only precision in the crafting of the historic architectural elements, but also a deft handling and transportation of these elements. A sandstone jaali/lattice screen taking over a month to be created, can easily snap if the craftsmen transporting them to the great heights in the monument are not careful. Installation of these features requires precision in planning and management too.