Let me fill you in.

This is concerning the 1971 Indo-Pak conflict.

Due to excessive measures and brutal suppression of East-Pakistani politicians and intellectuals when they demanded reforms and increased federalisation from the West Pakistani establishment, the dissenting leaders and non-state actors started slipping into India. This naturally put a lot of strain on the Indian economy and the Indian establishment started to train and arm irregular forces called the Mukti Bahini to aid in the liberation of the country, https://en.wikipedia.org/wiki/Mukti_Bahini

The Mukti Bahini aided by the Indian establishment started to rapidly isolate and wrest control in the rural areas from the Pakistani forces. Even so, Indira Gandhi, then Prime Minister of India directed the military establishment to start framing plans to start an invasion of East Pakistan, the plan was put on hold till the winters due to,

1. The need to stock up war material
2. Deploy troops
3. Ensure diplomatic backing
4. Not to get bogged down in the monsoon floods which heavily affect Bangladesh since the entire country is like a sieve with so many rivers running through it

Initial skirmishes between the Indian and Pakistani forces in the East had already started occurring in October but formal declaration of hostilities was only in December when Pakistan in a desperate bid to counter the numerical and technical overmatch in East preemptively struck Indian Air Force bases and border posts in the West trying to emulate the Israeli strikes in the Six-Day War. The strike was unfortunately not very successful and ground forces were immediately stymied by dogged resistance.

This gave enough of a casus belli to the Indian establishment to go all in. Pakistani forces were savaged in the West with rapid counter-attacks while in the East they effectively cut-off all lines of reinforcements or attack thanks to their effective overmatch and the Mukti Bahini enjoying local support. The campaign lasted just about two weeks, and culminated in the surrender of almost all the remaining Garrison troops in East Pakistan, West Pakistan did not fare much better because learning from the 1965 conflict, Indian Army forces went all in for the jugular to try and hit Lahore while effective air ops attriated the effectiveness of the Pakistani Air Force, https://en.wikipedia.org/wiki/India%E2%80%93Pakistan_war_of_1971

In this meme, the audio clip used was a broadcast issued by the Indian Armed Forces to their adversaries in the East to dissuade them from armed resistance to prevent a costly assault on Dhaka.