On 3 December, 1971, Prime Minister of India Shrimati Indira Gandhi was addressing a public meeting in Kolkata before dusk and a huge number of people of India and Bangladesh and foreign media also participated in the meeting. The entire ground was filled up. Suddenly she received a massage that Pakistan had attacked India in the western front. She immediately left for Delhi and on reaching there she was about to declare war. But she was advised to delay the declaration of war. Reason behind was that Bangladesh Air Force, “KILO” flight was going to attack Dhaka at 12:01 and Chittagong at 12:10 midnight. Attack was successfully carried out by Bangladesh Air Force. And Indira Gandhi declared war on Pakistan at 12:20 midnight and that was the official start of war against Pakistan by India and Bangladesh Mukti Bahini. BBC broadcast the news all over the world. The pilots of Bangladesh Air Force who participated in the attack were Air Vice Marshall Sultan Mahmud, Flt. Lt. Shamsul Alam, Capt. Akram Ahmed, Capt. Sahrfuddin Ahmed, Capt. Shahabuddin Ahmed and Flt Officer Badrul Alam.

On the other hand, the guerrilla warfare launched by Mukti Bahini intensified beyond the control of the Pakistani forces. October and November were the two worst months for the enemy forces as freedom fighters under the cover of the winter fog launched attacks one after another to break their mental strength.
Pakistan Air Force fighter planes bombarded some outposts on Pakistan India border. The field troops also got engaged in artillery bombardment on each other. The Indian Air Force achieved remarkable success when within the first 48 hours it achieved complete air superiority in the Eastern theatre of war. All the fighter planes kept at Kurmitola PAF base were totally destroyed. This enabled the advancing Indian army columns to move without any fear of detection even in daytime.
With supply from the air assured, the army did not have to be dependent on opening of roads, which were heavily defended by the Pakistanis. The five division-strong Indian forces advanced from three directions and secured choke points well in the rear. In their advance, village people came out and marched alongside the Indian army and Mukti Bahini boys chanting Joi Bangla slogan. They could sense that victory was quite near. They offered the troops food and water as they passed by one village after another.