What measures did Balban take to combat the Mongol threat?

Balban took various measures to combat the continuous raids of the Mongols. He ordered reconstruction of old forts and construction of new forts along the northwest frontier. He kept a strong standing army and appointed his two sons, Muhammad and Bughra Khan as governors of the frontier provinces. They inflicted a crushing defeat on the mongols when they invaded Punjab and thus, saved the country from Mongol menace.