Major N.J.Dutta Singh was deployed in Sri Lanka as part of the Indian Peace Keeping Force. As a company Commander he led the advance of the battalion east of road Vasavilan-Uramparai. He vigorously pressed and cleared pockets of resistance, facing heavy and accurate militant fire all through the night of 12 October 1987. On 13 October 1987, he covered the operation to extricate the Para Commandos and 13 Sikh L1. He, with one platoon, moved to a vantage point. This platoon provided the most crucial fire support, but soon came under an overwhelming attack by the militants. Unmindful of danger, Major Singh continued to fight. Eventually he brought out his khukri and with two more men, charged the militants and engaged them in hand-to-hand combat. They killed many militants, but ultimately lost their lives fighting.

Major N.J.D. Singh displayed conspicuous courage and valiant leadership in the face of militant attacks.