BANGALORE - Designers of the 17th century Taj Mahal, the finest piece of Mughal architecture, employed the same unit of measurement used by the Harappan civilization as far back 2000 BC, according to a study by an IIT-Kanpur professor. These units were used by builders in India till the British imposed their own units in the 18th century.The study by R. Balasubramaniam of the Indian Institute of Technology, Kanpur, and reported in the latest issue of Current Science, has for the first time shown that the unit of length called ‘angulam’ - mentioned in Kautilya’s treatise on statecraft “Arthasastra” dated 300 BC — was used without a break in India for over 3,900 years.