In 1962, India adopted a Forward Policy against the Chinese. It was Defensive initiatives to safeguard the territorial integrity of India. To circumvent the Chinese expansion into the disputed areas, Indian Army was to “go as far as practicable … and be in eff occupation of the whole frontier”.
In NEFA (North East Frontier Agency), Assam Rifles was tasked with setting up posts all along the McMahon Line.
Problems Faced in Implementation of the Policy: There were no roads. No modern military equipment, what little available was useless at the Himalayan heights, Army was not ready to conduct combat ops in narrow River valleys and over 7000 feet deep gorges.
By 20 July 1962 under the Forward Policy, 34 posts (8 in Kameng, 7 in Siang and 11 in Lohit Frontier were established in NEFA).
These were manned largely by Assam Rifles, incl one at Dhola, a little South of Namka Chu River on 4 Jun 1962, under the guidance of Capt Mahabir Prasad of 1 SIKH.
Slowly following Chinese recce and troops build up. Indian Army took up hurried defences along the Namka Chu River in the Tawang Sector. Ironically these troops from the 7 Infantry Brigade/4 Infantry Division were very fresh in the high-altitude area, had walked many Kms from the road H, were at lower heights than the Chinese and very close to the river. There were large gaps between the battalions. The area was thickly wooded. All to their disadvantage.
On night of 19/20 Oct, herds of Yaks crossed over Namka Chu R; the Chinese (PLA) were ascertaining the depth of water at their selected crossing places, detonating mines and breaching wire obstacles with the help of yaks.
By 5 AM on 20 Oct, PLA crossed the R on foot through gaps avoiding the guarded Bridges (narrow log bridges made by the herdsmen). Tele lines were cut. PLA contacted defenses of 7 Inf Bde units on a broad front from the defender’s rear. This was a smart and well-rehearsed tactical manoeuvre by the enemy against a thinly defended border.
Indian troops were taken by surprise when assaulted from the flanks and rear. 2 RAJPUT and 1/9 GORKHA deployed at Bridge IV, III and area between Bridge III and II fought gallantly but were soon over-powered.
Brigadier Dalvi, the Brigade Commander and his party withdrew towards Serkhim area through the Dhola pass. Enroute, he was separated from most of the others and was finally left with only Captain Talwar of 17 Para Field Regiment and a few Other Ranks. On 22 Oct they ran straight into a Chinese company near Serkhim and were captured.
By AN of 20 Oct, Chinese had driven back Indian troops from Bridges I to V from Namka Chu, Tsangle, Khinzemane and Tsangdhar. Brunt of the attack was borne by RAJPUTs, GORKHAs and Assam Rifles. 4 GRENADIERs and 9 PUNJAB had not been attacked.
Deciding to pull back all troops to line Hathungla -Chutangmu just after mid-day, GOC 4 Infantry Division spoke to COs of 4 GRENADIERs and 9 PUNJAB ordering them to withdraw to Hathungla. The battalions commenced their withdrawals but could not reach Hathungla, which was occupied by the Chinese early in the morn 21 Oct. Realising that the Div Tac HQ at Ziminthang would soon be attacked, Gen Prasad ordered its withdrawal to Tawang.
Units of 7 Inf Bde were overrun, giving stiff resistance to PLA. Tac HQs 4 Inf Div at Zimithang withdrew on 21 Oct to Tawang and subsequently to Dirang Dzong.