Also called kos minars or mile pillars, minars have been used to denote a distance of one mile on the roads for centuries in India. One kos is equal to 1.1 mile or 3.2 km. They were first built by Sher Shah Suri, the Afghan ruler. The tradition was picked up by the Mughal rulers on the important roads across the length and width of the country.
The rulers used the minars not only to measure the distance, but also provide shelter to the tired travellers. These minars were strong circular structures that stood 30 ft tall on platforms made of bricks or stone and covered with lime plasters. The minars, moreover, also helped in maintaining communication system in the vast empire.
The modus operandi was to transmit a message from person to person until it reached the destination. Sometimes small lodges or sarais were also built along the minars for travellers to rest overnight. Some of these minars were built along the GT road starting from Lahore and running through Karnal over to Delhi.
One of these was located close to plot no.79 in Karnal. One of the sarais was built on Gharaunda about 12 miles in the south of the city.