Most people, when they hear the word 'genocide' are inclined to think of the Holocaust, Turkish/Ottoman crimes against Armenians, the slaughter of Tutsis and moderate Hutus in Rwanda or the deeds of the Khmer Rouge in Cambodia.
One seems to be largely forgotten about although the numbers killed are comparable to nearly all of the above. In 1971, East Pakistan (now Bangladesh) was breaking away from West Pakistan and there is a lot of evidence that the Pakistan army committed dreadful atrocities against the Bangladeshi people.
After Indian and Pakistani independence in 1947, West Pakistan (now just Pakistan) and East Pakistan were one state albeit separated by some two and a half thousand kilometres of Indian territory. In reality there was little sense of nationhood and many West Pakistanis looked down on the "small and dark" Bengalis and were "embarrassed" to have them as compatriots. General Niazi who headed the Pakistani Forces in Bangladesh regarded it contemptuously as "a low lying land of low lying people".
Eventually, with Indian assistance, Bangladesh did break free but not before there was a bloodletting on a massive scale as the Pakistani army targeted doctors, intellectuals, the educated classes, students and anyone likely to form a core of resistance.
The total of 3 million killed might be an exaggeration and some commentators say it originated in a statement from the then Pakistani President, Yahya Khan who said of the Bangladeshis, "Kill three million of them and the rest will eat out of our hands". While most settle on a figure of 1.5m killed, the very lowest estimate seems to be about a half million slaughtered in 10 months of madness. Mass graves are still being found; accurate figures will never be known. If there is any evidence that can be undisputably neutral, it comes from US diplomatic staff appalled at the bloodletting and at the Nixon's administration's approach which was to avoid embarrassing Islamabad. See source 1 for the so-called "Blood Telegram".
This episode is of current interest because of recent events in Dhaka, the Bangladeshi capital, where the life sentence handed down to one Abdul Quader Mollah (a senior figure in the Jamaat-e-Islami party) for aforementioned crimes in 1971 has outraged ordinary Bangladeshis who wanted him condemned to death. In response, the parliament has amended a law so that it can appeal the apparent leniency of the sentence. One way or another, what with Pakistani indifference to what its army did, the scars of 1971 are still very raw.
2. Genocide Since 1945: Never Again? - SPIEGEL ONLINE
3. Shahbag Square - why we Pakistanis don't know and don't care
4. Bangladesh amends war crimes law, mulls banning Islamists | Reuters