Humayun's tomb is known as the first example of the monumental scale that would characterize subsequent Mughal imperial architecture. Commissioned, it is believed, by Humayun's senior widow, Haji Begam, or by her son Akbar, the tomb is the first to mark the grave of a Mughal emperor; Humayun's father Babur, who founded the dynasty, had requested out of piety that he be buried in a garden. Humayun's Tomb is now one of the best-preserved Mughal monuments in Delhi.

The objective of the project was to revitalise the gardens, pathways, fountains and water channels of the chahar-bagh, or four-part paradise garden surrounding Humayun's tomb in Delhi, according to the original plans of the builders. Site works encompassed a variety of disciplines, including archaeology, conservation science and hydraulic engineering. 

The US$ 650,000 restoration project has featured the removal of 3000 truckloads of earth (12,000 cubic meters), the planting of 12 hectares of lawn, the re-setting and alignment of over 3,000 km of path edging, the preparation by some 60 stonecutters of 2,000 meters of hand-dressed red sandstone slabs (to edge the channels), the creation of 128 ground water recharge pits, the creation of a site exhibition, and the planning and installation of a new water circulation system for the walkway channels. To ensure that water flows naturally through the channels and pools on the 12-hectare (30 acre) site without the aid of hydraulic systems, the water channels had to be re-laid to an exacting grade of one centimetre every 40 metres (1:4000 scale). Over 2500 trees and plants, including mango, lemon, neem, hibiscus and jasmine cuttings, were planted in the gardens. Long-dormant fountains have come to life.

The rehabilitation project undertaken by the Aga Khan Trust for Culture included the following main elements: 

Reinstating the walkways and conserving the edging stones;

Repair, extension and reactivation of the irrigation system;

Establishing water sources for the water channels and irrigation system, including a pump station for a water recycling system;

Conserving, repairing and rebuilding, where necessary, the water channel system;

Re-levelling the planted zones and revitalising them with species and arrangements that conform to the customs and patterns of Mughal sources; and,

Supporting research that informs the conservation and restoration process, contributes to the development of educational materials for use in schools of architecture, conservation, and heritage management, as well as visitors to the Tomb.

Source: Aga Khan Trust for Culture Historic Cities Programme