Lance Naik Jangbir Singh was performing the duties of Light Machine Gun Number 1 with Number 14 Platoon of Echo Company 4 Garhwal Rifles. The Company had been tasked to advance, contact and reduce a militant camp in the Nayraoo lagoon area of Northern Vavuniya Sector (Sri Lanka). On 22 March 1989 the leading platoon of the Company contacted the militants. A fierce exchange of fire ensued resulting in casualties in the platoon. It was at this time that Number 14 Platoon, to which Lance Naik Jangbir Singh belonged, was tasked to move towards the southern flank. Lance Naik Singh was ordered to move his detachment to a point approximately 30 metres away and engage the militants so that the rest of the platoon could pull back to a safe area. In the dash to the indicated point under heavy fire, Lance Naik Singh was separated from Number 2 of his detachment, and thus reached there alone. Unmindful of the fact that he was alone, he immediately engaged the militants with sustained and accurate fire. The Platoon Commander then regained balance and redeployed his platoon some 30 metres behind the area where contact had been made. However, Lance Naik Singh's position came under heavy automatic fire and an RPF rocket burst above, injured him in the shoulder.

Though isolated, under great stress and in pain, Lance Naik Singh continued firing accurately. By the time, the platoon Havildar returned to rescue Lance Naik Jangbir Singh, the latter was hit by a burst of militant fire and killed.

Lance Naik Jangbir Singh displayed conspicuous courage and valour in action against the militants.