For example, the total height of the pillar is exactly 4 'dhanus', Balasubramaniam told IANS.

And now in a paper published in Current Science, Balasubramaniam has shown that the modular plan of the Taj Mahal complex is based on use of grids of sides measuring 60 and 90 'vitasti'.

He says the study has established that the design and architecture of the Taj is based on traditional Indian units codified in 'Arthasastra' and that 'there is nothing foreign' in its design.

'The fact that the unit of angulam of 1.763 cm could match very well the dimensions of historical monuments establishes the continuity of India's engineering tradition through the ages for as long as 3,900 years,' says Balasubramaniam in his paper.

'With the new knowledge we can analyse all the important ancient structures in India,' he says, and hopes the findings 'will open a new chapter in the study of metrology (science of measurements)'.

But how did the 'angulam' tradition remain unbroken for so long?

As quoted in the website of 'Nature India', Balasubramaniam believes the workers from the Harappan days were perhaps using some kind of scale 'that was handed over through generations'.