Operation Chengiz Khan

5:40 p.m., 3 December 1971

At approximately 5:40 p.m. on 3 December 1971 the Pakistan Air Force began pre-emptive strikes against Indian airfields in the western theatre, under the code name Operation Chengiz Khan. Air Chief Marshal Abdur Rahim Khan led the force, whose objective was temporary air superiority in the west.

Pakistan also opened or intensified ground and artillery operations along the western frontier, and told the United States that the raids were countermeasures against Indian operations already under way.

How many airfields, and where the leaders were

An IDSA military history identifies 11 northwestern Indian airfields as targets. Indira Gandhi's later official account named eight: Amritsar, Pathankot, Srinagar, Awantipur, Uttarlai, Jodhpur, Ambala and Agra.

Gandhi was in Calcutta when the attacks began; India's defence minister was in Patna and its foreign minister in Bombay. She returned to New Delhi, addressed the nation that night, described the action as a full-scale attack and said India had no option but to adopt a war footing.

What “begins” elides

The Indian Air Force retaliated against Pakistani bases that night, so the operation neither caught the entire force on the ground nor prevented an immediate response. On 4 December India formally notified Pakistan through Switzerland that a state of war existed, and a joint India–Bangladesh command was established for the final campaign.

Calling 3 December the war's absolute beginning is disputed: the Bangladesh Liberation War had run since March, about 10 million refugees from East Pakistan were sheltering in India, and Indian and Pakistani forces had already fought inside East Pakistan in November.

Contemporary US intelligence concluded it could not determine with certainty which side initiated the broader western-front fighting that day, though the Pakistani air strikes themselves are undisputed.