Short answers, pulled from the story.
A Mughal garden is a type of garden built by the Mughal emperors of South Asia, derived from the Persian charbagh tradition. Its main features include rectilinear layouts within walled enclosures, pools, fountains, canals, and the highly disciplined geometry that distinguishes it from Central Asian predecessors.
Babur, the founder of the Mughal Empire, is credited with building the first charbaghs in South Asia. The Aram Bagh of Agra is thought to have been the first charbagh in the region. Babur also had gardens built in Lahore and Dholpur.
The Mahtab Bagh was a night garden built by Shah Jahan across the Yamuna river from the Taj Mahal at Agra. Its pavilions were faced with white marble to glow in moonlight, and the garden was planted with night-blooming jasmine and other pale flowers. It was part of Shah Jahan's broader vision connecting the Taj Mahal garden complex.
The Mughals used four principal water sources: lakes or tanks, wells or step-wells, canals harnessed from rivers, and natural springs. Geared Persian wheels called saqiya lifted water to feed the channels, while terra-cotta pipes and water-chutes called chaadar distributed it under hydraulic pressure. The Shalimar Bagh in Lahore alone had 450 fountains, capable of throwing water 12 feet into the air.
The tulip was adopted as a personal symbol by the emperor Shah Jahan. It was used as the most important of the scrolling naturalistic floral motifs inlaid with semiprecious stone in the marble of the Taj Mahal and the Mahtab Bagh.
Constance Villiers-Stuart wrote the first serious historical study of Mughal gardens, published in 1913 under the title Gardens of the Great Mughals. She was consulted by Edwin Lutyens, which may have influenced his choice of Mughal style for the Viceroy's Garden in 1912.