Indian shot putter Inderjeet Singh said on Tuesday that he has been notified by the national anti-doping agency (NADA) that he has returned a positive test for banned substances in his A sample.Inderjeet, who won the gold medal at the Asian Athletics Championships in 2015, told local television that he had been informed of the test late on Monday and that all his earlier tests had been negative.Navin Agarwal, the director general of NADA, told Reuters an athlete's A sample had tested positive."The athlete has been notified and given the right to get his B Sample tested," he said, without identifying the athlete.