India, June 30 -- New Delhi

Presumed ancient carvings dotting the quartzite rocks of Delhi's Central Ridge, not too far from the Delhi Polo Club, were discovered over the past week and mark the first likely record of a petroglyph in the Central Ridge, environmentalists who made the discovery said.

Such rock carvings have previously been discovered around the Jawaharlal Nehru University (JNU) campus, while prehistoric stone tools have also been documented around the Kamla Nehru Ridge in north Delhi. Neighbouring Bhondsi, Surajkund, Mohabatabad, Dhauj, Kot, and Alwar were found to host multiple such rocks, tools and engravings, experts said.

Environmentalist Pradip Krishen, who made the discovery alongside environmentalist Chetan Agarwal...