Q. The tax called Haque-i-Sharb or Hasil-i-Sharb imposed by Firoz Tughlaq was on __?
Answer: Irrigation
Notes: Firoz Shah Tughlaq was the first Sultan to impose a water tax and built canals, including the Yamuna canal. He established the Diwan-i-Khairat for public works, funded irrigation projects through water taxes, and promoted agriculture by providing loans to farmers and encouraging cash crops like sugarcane and cotton. His reign advanced infrastructure and the agrarian economy.