The War of 1965 between India & Pakistan

The five-week war caused thousands of casualties on both sides. It ended in a United Nations (UN) mandated ceasefire.
This war saw the largest amassing of troops in Kashmir since the Partition of India in 1947, a number that was overshadowed only during the 2001-2002 military standoffs between India and Pakistan. Most of the battles were fought by opposing infantry and armoured units, with substantial backing from air forces.
Pakistan was concerned by attempts of India to absorb Kashmir - a state internationally recognised as "disputed", into the Indian Union. The basis for this claim was Articles 356 and 357 of the Indian Constitution that allow the President of India to declare President's Rule in the disputed state.
On August 15, 1965, Indian forces crossed the ceasefire line and launched an attack on the region referred to by the disputants as either Azad Kashmir.
On September 1, 1965, Pakistan launched a counterattack, called "Operation Grand Slam", with the objective to capture the vital town of Akhnoor in Jammu, which would sever communications and cut off supply routes to Indian troops. Pakistan progressed against Indian forces, who were caught unprepared and suffered heavy losses. India responded by calling in its air force to blunt the Pakistani attack. The next day, Pakistan retaliated, its air force attacked Indian forces and air bases in both Kashmir and Punjab. It became one of the turning points in the war when India decided to relieve pressure on its troops in Kashmir by attacking Pakistan further south.
Pakistan's BRB Canal was a vital barrier that needed to be crossed by Indian troops. This bridge across the canal was destroyed by the Pakistan Army. India crossed the International Border on the Western front on September 6, marking an official beginning of the war. On September 6, the 15th Infantry Division of the Indian Army, under World War II veteran Major General Prasad, battled a massive counterattack by Pakistan near the west bank of the BRB Canal, which was a de facto border of India and Pakistan. The General's entourage itself was ambushed and he was forced to flee his vehicle. A second, this time successful, attempt to cross the BRB Canal was made over the bridge in the village of Barki, just east of Lahore. These developments brought the Indian Army within the range of Lahore International Airport.
One unit of the Jat Regiment, 3 Jat, had also crossed the BRB canal and captured the town of Batapore on the west side of the canal. The same day, a counter offensive consisting of an armoured division and infantry division supported by Pakistan Air Force Sabres forced the Indian 15th Division to withdraw to its starting point.
India's 1st Armoured Division, labelled the "pride of the Indian Army", launched an offensive towards Sialkot. The Division divided itself into two prongs, came under heavy Pakistani tank fire at Taroah and was forced to withdraw.
The war was heading for a stalemate, with both nations holding territory of the other.
War saw the Indian Air Force and the Pakistani Air Force engaged in full scale combat for the first time since independence.
The Pakistan Air Force (PAF) shot down 104 IAF planes, losing only 19 in the process.

Pakistan's main strike force comprised the U.S. made F-86 Sabre jets, which claimed a fair share of Indian planes. The F-104 Star fighter of the PAF was by far the fastest fighter plane operating in the subcontinent at that time. Unlike the PAF, whose planes largely consisted of American craft, the IAF flew an assortment of planes, from Vampires to Hawker Hunters, many of which were outdated in comparison to PAF planes. This gave an edge to the PAF to achieve some of the historic dog fight records.
The 1965 war witnessed some of the largest tank battles since World War II.
India's attack at the Battle of Chawinda, led by its 1st Armored Division and supporting units, was defeated back.
Pakistan's PNS Ghazi, was the only submarine operated by either of the warring nations in 1965. On September 7, a flotilla of the Pakistani Navy carried out a small scale bombardment of the Indian coastal town and radar station of Dwarka, which was 200 miles (300 km) south of the Pakistani port of Karachi.
One submarine, PNS Ghazi, kept the Indian Navy's aircraft carrier INS Vikrant besieged in Bombay throughout the war.
On September 22, the United Nations Security Council unanimously passed a resolution that called for an unconditional ceasefire from both nations. The war ended the following day.
The Soviet Union, led by Premier Alexey Kosygin, hosted ceasefire negotiations in Tashkent (now in Uzbekistan), where Indian Prime Minister Lal Bahadur Shastri and Pakistani President Ayub Khan signed the Tashkent Agreement, agreeing to withdraw to pre-August lines no later than February 25, 1966.
The "Official History of the 1965 War", drafted by the Ministry of Defence of India in 1992, was a long suppressed document that revealed some truths. According to the document, on September 22 when the Security Council was pressing for a ceasefire, the Indian Prime Minister asked commanding Gen. Chaudhuri if India could possibly win the war, were he to delay accepting the ceasefire. The general replied that most of India's frontline ammunition had been used up and the Indian Army had suffered considerable tank losses.

The war had created a tense state of affairs in its aftermath. Though the war was indecisive, India suffered much heavier material and personnel casualties compared to Pakistan. Many war historians believe that had the war continued, with growing loss and decreasing supplies, India would have been eventually defeated. Pakistan's decision to declare ceasefire with India caused some outrage among the Pakistani populace, who believed they had the upper hand.
At the conclusion of the war, many Pakistanis considered the performance of their military to be positive. September 6 is celebrated as 'Defence Day' in Pakistan, in commemoration of the successful defence of Lahore against the Indian army. The performance of the Pakistani Air Force, in particular, was praised.