Evidence of 65 burials has been unearthed over the past month at the site in Farmana, 60-odd km from Delhi, making it the largest Harappan burial site found in India so far.

The digging is in its third season now. Evidence of seven burials was discovered last year, and should the work continue into another season, experts say Farmana may throw up evidence of a larger number of burials than even Harappa, the Pakistani Punjab town from which the civilisation of the Indus valley (c. 3300 BC-1300 BC) takes its name.

The discovery holds enormous potential, said Prof Vasant Shinde of the Department of Archaeology, Deccan College Post-Graduate and Research Institute, Pune, the director of the excavation project.

“With a larger sample size it will be easier for scholars to determine the composition of the population, the prevalent customs, whether they were indigenous or migrated from outside,” Prof Shinde said.

A century-and-a-half after the great civilization was discovered, historians still have no definite answers to a number of questions, including where the Harappans came from, and why their highly sophisticated culture suddenly died out.

“For the first time, we will conduct scientific tests on skeletal remains, pottery and botanical evidence found at the site, to try to understand multiple aspects of Harappan life,” Prof Shinde said.

“DNA tests on bones might conclusively end the debate on whether the Harappans were an indigenous population or migrants. Trace element analyses will help us chart their diet ¿ a higher percentage of zinc will prove they were non-vegetarians; larger traces of magnesium will suggest a vegetarian diet.”

Most chemical, botanical and physical anthropology tests will be done at Deccan College. But the more sophisticated and expensive DNA and dating tests will be conducted in Japan. The Research Institute for Humanity and Nature, Kyoto and Maharshi Dayanand University, Rohtak, are collaborating with Deccan College under the aegis of the Archaeological Survey of India for the project.

The team also plans to carry out coring tests in lakes around the Farmana site to ascertain climatic conditions prevalent at the time of the Harappan civilization, and investigate whether the decline of the culture followed catastrophic climate change.

The burials found so far are expected to be from around 4509 BP (before present), or 2600-2200 BC. “There are three different levels of burials and at some places skeletal remains have been found one above the other. All the graves are rectangular ¿ different from other Harappan burials sites, which usually have oblong graves,” Prof Shinde said.

The site shows evidence of primary (full skeleton), secondary (only some bones) and symbolic burials, with most graves oriented northwest-southeast, though there are some with north-south and northeast-southwest orientations as well. The variations in burial orientation suggests different groups in the same community, Prof Shinde said. The differences in the numbers of pots as offerings suggest social and economic differences within the community. Also in evidence are significant signs of regional variations that contest the idea of a homogenous Harappan culture.

Prof Upinder Singh of the Department of History, Delhi University, expressed enthusiasm about the project. “If such a large Harappan cemetery has been discovered, I am sure it is going to be of significant help in historical research,” she said. “The entire fraternity of research scholars and academics would be looking forward to knowing about the findings at the site.”