Concept:
The Mughal state invested heavily in agricultural infrastructure to boost land revenue. The maintenance and expansion of artificial irrigation systems, such as wells, reservoirs, and extensive canals, were key to bringing arid lands under cultivation.
Step 1: Analyzing historical canal engineering under the Mughals
The Shah Nahar was originally a canal system built during the Sultanate era. Over time, it accumulated silt and fell into disuse.
Step 2: Identifying the ruler responsible for the repair work
During the seventeenth century, the Mughal Empire experienced a golden age of architecture and civil engineering under Emperor **Shah Jahan**. Recognizing the irrigation needs of the Punjab region, Shah Jahan ordered his engineers, led by the noble Ali Mardan Khan, to clean, restore, and extend this vital water channel. The renewed canal brought water from the Ravi River to irrigate imperial gardens and agricultural fields, significantly boosting regional productivity. Thus, the correct option is Shahjahan.